The next day, a group of eight trainers of varying ages were all making their way through Lumiose City to Prof. Sycamore's laboratory, forming a tight clump as they walked. Ash and his friends had all deduced that if everyone else surrounded Serena, forming a protective barrier, passersby were far less likely to approach her and ask for autographs and photographs the like. She didn't hate the attention, and she always enjoyed making other people happy, but they had an appointment to keep. Madison joked that Serena now had her own entourage, which caused the older girl to roll her eyes, and everyone else to laugh.

They all spread out as they entered the lab, and Ash walked up to the front desk. "Hi again. We have another appointment to see the professor?"

"Yes, of course," the receptionist answered with a polite smile. "He's stepped out for a moment, but-"

"We can take care of them, Maribelle."

Both Ash and the receptionist looked over, and the young trainer gasped as he saw who was speaking. The voice belonged to a familiar young man around Brock's age, with short black hair that matched his ensemble of clothes. Besides him was a younger, redheaded girl clad in green, roughly Ash's age, but slightly shorter.

"No way!" A grin spread wide across Ash's face. "Alain! Mairin!" He quickly walked over and extended his hand toward his formal rival, the one who had defeated him in the finals of the Kalos League five years ago. As the two shook hands, Serena rushed up to clasp hands with the redhead next to them.

"I can't believe you're here! It's great to see you again!" she exclaimed, as Clemont and Bonnie gathered around as well, eager for their own reunion. The foursome behind them walked up curiously, starting to get used to Ash or Serena recognizing everyone they met.

"I'm guessing you're friends with these two," Brock joked.

"Yeah, we are!" Ash took a step back, gesturing behind him. "Guys, this is Brock…" He gave a quick introduction of the four friends behind him, each of whom smiled and waved in turn.

"Good to meet all of you," the older boy answered. "My name's Alain. I work on and off doing research under Professor Sycamore. I spend the rest of my time as a Pokémon Trainer."

"And I'm Mairin," the redhead chimed in. "I'm Alain's research assistant."

"She's my travel partner," he corrected.

"He depends on me for all sorts of research stuff," Mairin continued, as if he hadn't said anything. "I don't know how he gets anything done without me."

"She's a remorseless liar," Alain deadpanned. "Don't listen to a word she says."

Ash chuckled, as Serena spoke up. "How have you been doing, Mairin? How is Chespie?" she asked, referring to the girl's Chespin.

"I've been great!" Mairin answered. "And he's not Chespie anymore, he's Quillie now!"

"Oh! That's wonderful news! You'll have to show me later!"

"What about you, Alain?" Ash asked, looking up. "How has your Pokémon training been going? Have you been improving since the Kalos League?"

"Well…" Alain folded his arms, thinking. "It's more research, less training these days. No more nose to the grindstone, constant battling. I have more work to do."

Ash nodded. "That's too bad. Do you still get to battle, though?"

"Oh, yes. There's a certain someone who makes sure I'm battling at least once a week." He cast his eyes down to the girl beside him.

"Well, I need the practice!" Mairin insisted. "I need to get better at using Mega Evolution! And you don't want to get rusty, do you?"

"Mega Evolution?" Ash's eyebrows raised. "Mairin, you have a Pokémon that can Mega Evolve?"

"Sure do!" She grinned wide, raising her arm to reveal a Mega Ring around her wrist. "I got my hands on a piece of Pinsirite a couple of months back. A few weeks ago, my Pinsir Mega Evolved for the first time!" She was giddy, bursting with excitement at the memory even now. Mega Evolution had always been a fascination of hers.

"A Mega Pinsir!" Ash's eyes lit up. "I've got to see that! How about you and me battle? Your Pinsir versus my Greninja!"

"Really?!" Her fists clenched tightly. "That'd be so great! Let's do it! Come on!" She spun around and began to lead Ash down a hallway, toward the battlefield behind the lab, running much faster than she intended in her eagerness.

Iris adopted an amused smile. "I can't tell which of them is more excited."

"Me neither," Brock added. "I thought it was impossible to like Pokémon battles as much as Ash does."

Alain sighed. "Come on. We should make sure they don't destroy the lab." He led the rest of the group through the laboratory, heading for the battlefield at a more leisurely pace.

"So, Alain…" Clemont walked ahead of the group, side by side with the one leading them. "You said you were doing research. What have you been studying?"

Alain nodded. "I've been studying the synthetic Mega Stones that Team Ace has been selling. I'm trying to figure out how they're making them."

"What have you found out?" Serena asked. "Is there anything strange about them?"

"The whole thing is strange," he answered, sounding a little defeated. "It shouldn't be possible, but they're perfectly functional Mega Stones. They have a different… composition, but they give off the same energy and everything. I've been looking at them for nearly a year, but I still haven't found out much. And they won't tell me anything."

"But they really Mega Evolve Pokémon?" Shannon piped up. "Is there anything strange about how they evolve?"

"No, it's the same as organic Mega Stones, as far as we can tell." Alain glanced back. "You'll see for yourself in a minute. Mairin's using synthetic Pinsirite. She's 'borrowing' it from the lab… indefinitely."

The group of eight stepped outside, finding Ash and Mairin on opposite sides of a simple dirt battlefield. Greninja was standing stoically on one end of the arena, while on the other end, Mairin stood behind a brownish-gray Bug-type Pokémon, with two large pincers atop its head, and a necklace draped around its neck with a Mega Stone embedded in it.

"You ready, Ash? Let's do this!" Mairin raised her arm and grasped her Mega Ring tightly, not waiting for Ash's answer. Everyone watched as the stone glowed, light shining from between her fingers, and the Mega Stone on Pinsir's neck began to glow as well, with a familiar rainbow light. Ash's eyes were shining with amazement as he watched Pinsir grow and shift, forming a pair of orange and yellow wings. As the glow faded, he could see Pinsir's normally white eyes were now a bright and threatening yellow, locking in on Greninja across the way.

"That's so cool…!" Ash was grinning from ear to ear, his heart racing before the battle had even begun. "Alright, Greninja, let's-"

His command was interrupted by a sound from his belt. He looked down to see that one of the Poké Balls attached to his hip had opened itself, and moments later, Houndour had emerged onto the battlefield, growling and snarling.

"Whoa! Houndour, what are you doing?" The Pokémon ignored him, baring his fangs as he raced toward Mega Pinsir, eliciting gasps from several of the people watching. He leaped into the air, fangs glowing red with fiery heat.

Mairin acted quickly. "Pinsir, grab him before he can hurt you! Be careful!" Her Pokémon stepped forward, snatching Houndour's midsection in his pincers, just hard enough to restrain the Pokémon without hurting it. Houndour snarled and snapped at the air, trying to wriggle himself free.

"Geez, what is his deal?" Iris wondered aloud, as Ash ran out onto the battlefield. "First the food thing, now this? Why can't that Pokémon behave?"

"It sort of seems like he has a chip on his shoulder, doesn't it?" Serena added. Madison and Shannon nodded in agreement, as Ash pulled out Houndour's Poké Ball.

"Sorry, Houndour," he offered as he returned the Pokémon. "I'll have you battle another time, alright?" He glanced across the way at his opponent. "Sorry about that. I'm looking after Houndour for someone else, and he's a bit of a handful right now."

"He's just excited to battle," Mairin replied, taking it in stride. "You and I can relate to that, right?" Ash smirked and nodded, before jogging back to his position on the battlefield, his focus quickly returning.

"Come on, Greninja, let's show them what we've got!" Trainer and Pokémon struck identical poses, their breathing slow and steady as they worked to synchronize with each other. Seconds later, Mairin gasped as Ash's Pokémon was surrounded by a thick shield of water; when the water fell away, the Pokémon had taken the form of the mysterious Ash-Greninja.

Iris, Brock and Shannon were all gawking in stunned amazement at the transformation, having never seen it before, or anything quite like it. As they tried to find words to express what they were thinking, Clemont chuckled and began to explain their limited knowledge of the Bond Phenomenon.

Mairin was vibrating with excitement as she gave her first command. "Pinsir, fly up in the air, then come down and use X-Scissor!" Her Pokémon leaped fifteen feet into the air, before turning and diving toward his opponent, his claws glowing white as they crossed each other in an X shape.

"Match that with an Aerial Ace, Greninja!" Ash commanded. His Pokémon ran forward, crossing his arms as well, as they began to glow purple. The two attacks met in the middle of the arena, as the combatants strained against each other. It was Greninja who ultimately won out, slicing his arms forward and forcing Pinsir back.

"Great work!" Ash called out, as Pinsir worked to right himself. "Now use Double Team!" Immediately, Greninja's form began to duplicate itself, more than a dozen copies of the Pokémon appeared on the battlefield. Pinsir whirled around in the air, trying to discern which one was real.

Mairin was unfazed, having too much fun to be frazzled. "Start swooping down and using Vise Grip! Find the real one!" Her Pokémon swooped down toward the first Greninja he saw, trying to grab it in his pincers; it vanished into the air, having been only an illusion. He continued flying, undeterred, taking out one false Greninja after another, failing to find his target.

"Now! Use Cut!" Ash eventually shouted. Pinsir started and looked around, trying to find which Greninja was moving, spotting one leaping toward him with a blade of light. Greninja swung down as hard as he could, sending Pinsir crashing down to the ground, as Serena and Bonnie both cheered loudly.

Ash grinned wide, delighted with his Pokémon's performance. "Great work! Go in and use Cut again!" Greninja landed on the ground and dashed forward, ready to continue his assault, as Pinsir got to his feet as fast as he could.

"You can take that, Pinsir!" Mairin ordered. "Use Harden!" Pinsir stood his ground, glowing white for a moment, and when the light faded his body appeared to be covered with a metallic sheen. As Greninja swung his blade again, Pinsir dug his feet into the ground, tanking the hit with little more than a grunt, barely budging.

"Quick, use X-Scissor!" Mairin followed up. Her Pokémon stepped forward, crossing his arms and swinging them at Greninja, knocking him back before he had time to dodge. He quickly rolled and got back on his feet, but his trainer was not so lucky.

"Agh!" Ash felt himself being knocked backward just as Greninja was, bracing himself with his arms to avoid falling onto his back. He could hear gasps from around the room, followed by footsteps.

"Ash!" Serena was beside him in an instant, kneeling next to him. "You're not hurt badly, are you?" Bonnie, Clemont and Iris were soon surrounding him as well, as he got to his feet, assuring them that he was fine.

"What? What happened?" Mairin's tone was panicked, as she watched Ash stand up while holding his chest. "Why is he hurt?"

"That's one of the effects of the Bond Phenomenon," Alain explained, standing behind her. "Ash suffers some of the damage that Greninja takes in battle."

"What?! I didn't know that!" She looked back at him with an expression of worried guilt, as if she had punched Ash herself.

Alain raised an eyebrow. "How did you not know that? You were there at our battle in the Kalos League, weren't you?"

"Yeah, but I was watching you, not him!" she protested.

"Maybe we should call this battle here." Everyone turned to look at the door to the laboratory, where Prof. Sycamore was standing with his hands in his pockets. "Looks like things might be getting a bit too intense."

"Yeah…" Mairin looked toward the ground, the wind taken out of her sails. "Sorry, Ash. Sorry, Professor."

"It's fine!" Ash insisted, walking onto the battlefield. "I've taken way worse hits from Alain, trust me." Mairin turned back to glare at the older boy, who looked a bit flustered at being put on the spot.

The professor chuckled. "Ash will be just fine, I'm sure. Now, let's get inside and get some testing underway, shall we?" Ash nodded, slowly exhaling as he carefully broke his sync with his Pokémon, the transformation reverting itself. Once he had regained his footing, he followed the professor inside, along with the large crowd of people accompanying him.

Ten minutes later, Ash was standing still, arms held out at his sides, as Alain applied a number of electrical diodes to his body, connected by wires. In another part of the room, Prof. Sycamore was doing the same thing to Greninja. The others were spectating from the opposite side of the room, giving the boy and his Pokémon some space.

"What do all these wires do, anyway?" Ash wondered aloud.

"They'll give you an electric shock if you screw the test up," Mairin explained helpfully.

"They what?!" Ash started to grab at the wires in a panic. "Get these off me!"

"They're not for shocking!" Alain insisted, grabbing at Ash's hands to stop him from ripping the diodes off. He shot an angry glare at his redheaded companion, who was biting her lip to keep from laughing.

"The wires are to measure your vitals," Sycamore explained more calmly. "Heart rate, brain waves, breathing, all that. This way, we can measure how synchronized you are with Greninja."

"Alright…" Ash was still wary as Alain attached the final diode, stepping away. "So how many of these tests do you want us to do?"

"Well, if my hypothesis is right, we'll only need to do one." The professor stepped away from Greninja as well, as the Pokémon continued to stand nonchalantly, as if nothing strange was happening. "If I'm wrong, we'll have to do a few more. I'm not sure exactly how many. But I won't keep you all day, I promise."

Ash nodded, hoping that the professor's idea was correct, whatever it was. "So what do you want me to do first?"

Sycamore stepped back to get a better view of both Ash and Greninja, as did Alain. "First, I want you to show us the Bond Phenomenon in action. Do what you did before to bring out Greninja's transformation."

The trainer nodded, giving his Pokémon a resolute look. Both of them focused on their slow and steady breathing, as they did out on the battlefield, putting themselves in sync. After a few seconds, the familiar water veil appeared around Greninja, transforming him into Ash-Greninja. The professor watched the Pokémon closely the entire time, noting all of the small changes as they happened.

Ash watched as Alain and the professor looked at the monitors around the lab, taking notes and writing down measurements. Once they were done, the professor looked back at Ash. "Alright, you can relax now. Please end the transformation." He nodded and exhaled, and Greninja reverted to his base form after a few moments. Ash could feel himself getting used to the phenomenon once again, no longer being knocked off of his feet when his Pokémon returned to his old self.

"Was that the first test?" he asked. "Did you learn what you needed to know?"

"No, that wasn't the first test." Sycamore walked over to Ash, inserting his hand into his coat pocket. "I'd like for you to do that once more, but this time, hold onto this." He withdrew his hand and extended it toward Ash, holding out a small, round, rainbow-colored crystal.

"A Key Stone?" The boy reached out and took it. "This won't do anything, will it?"

"We're about to find out." The professor stepped back. "Whenever you're ready, Ash."

Ash looked down at the stone in his hand, highly skeptical, but willing to try it for Prof. Sycamore's sake. He took a deep breath and started the synchronization process once again, his hand closing around the Key Stone. Immediately, streams of rainbow light began to shoot out from his fingers, causing him to jump and nearly drop the object. He turned his attention toward Greninja, eyes widening as the Pokémon began to glow with a bright light. His face began to shift and widen, his muscles growing slightly larger, a giant shuriken of water forming on his back. When the light finally faded, the figure that remained was the spitting image of Ash-Greninja, but with one critical difference: the black hair, and everything else that made him look more like Ash, was nowhere to be found.

"Whuh… what?!" Ash was stunned, rendered immobile by the shock, as were many of the spectators. Greninja himself seem taken aback as he looked down at himself, hands moving up to feel his head. "What happened?!"

"So, my hypothesis was correct after all." Sycamore looked immensely pleased with himself as he stepped forward again. "What we have here is the first known appearance of a Mega Greninja."

The room continued to stare in stunned silence, the whirring machinery around them providing the only noise.

"Professor, could you tell us what you've learned about the Bond Phenomenon? Can you explain why the Key Stone worked?"

Several minutes later, in a comfortable lounge with several chairs and a sofa, an intensely curious Clemont was quizzing the professor about his findings, as everyone else sat or stood around. Ash and Greninja were no longer attached to anything, their biometric data no longer being needed.

"There's a lot to cover, but sure I can," Sycamore responded. "My hypothesis was that the Bond Phenomenon was another method of achieving Mega Evolution. I think today has proven that to be correct."

"So when we use the Bond Phenomenon, Greninja is Mega Evolving?" Ash was sitting up straight, more fascinated than anyone, except possibly Clemont. "But how does that work?"

"Well, let's start at the beginning." The professor had a glint in his eyes, as he transitioned into Scientist Mode. "Normally, you need two things to Mega Evolve: a Key Stone and a Mega Stone. But what are those two things for?" He could see everyone's eyes on him, relishing the moment.

"A Key Stone, we've found, is a crystal that can synthesize a strong bond between trainer and Pokémon. It bridges the gap between the two of them, and allows them to synchronize. But…" He cast his gaze down at the young trainer in front of him. "As Ash and Greninja have proven, it's possible to achieve this level of synchronicity without a Key Stone, if the two are close enough and have absolute trust in each other. It can even cause the Pokémon to change in ways that make it more like its trainer, as you know. This may well be the very first kind of Mega Evolution ever discovered, long ago."

"So without a Key Stone, Greninja becomes Ash-Greninja," Serena spoke up. "But with a Key Stone, he becomes Mega Greninja instead? Because of… something the Key Stone does?"

Sycamore nodded. "From what we've observed, a Key Stone makes the bond easier to achieve, but it also makes the bond weaker than it could be. Ash and Greninja have a stronger bond than they could achieve using a Key Stone, which is why we get Ash-Greninja instead of Mega Greninja."

"So why hasn't anyone ever seen a Mega Greninja before?"

The professor smiled and shrugged. "Nobody's ever found a Greninjite." Serena blinked and sat back, not sure what answer she was expecting.

"So if a Key Stone isn't needed after all, is it something special about the trainer?" Brock asked, sitting up. "Is there something about humans that makes Mega Evolution work?"

"That's a good question." The professor rubbed his head. "For all the research we've done, we've never found anything specific to humans that makes Mega Evolution happen. They might not be important at all. There have been some recorded instances of Pokémon undergoing Mega Evolution all by themselves, without bonding with anyone else. For all we know, Pokémon could be Mega Evolving each other. We've still got a lot to learn about the process."

Clemont nodded, listening intently. "That's a little bizarre, but it makes a lot of sense. But… what about the Mega Stone? That's even more important than the Key Stone, isn't it?" Behind him, Bonnie was trying her best to follow along with the discussion, as was Mairin.

"Now that's the really fascinating part." Prof. Sycamore began to grin excitedly. "After years of study, we finally have a better idea of what a Mega Stone is. Each Mega Stone is a standard evolution stone that's been irradiated with Mega Energy. The sort of Mega Stone it becomes depends on what the original evolution stone was, and the exact circumstances of how it was irradiated. But this stone is what generates the Mega Energy needed to perform Mega Evolution. And the sort of energy that's emitted can usually only evolve one species of Pokémon."

"Where does this Mega Energy come from?" Iris asked. Brock nodded beside her, indicating that he was thinking the same thing.

"It depends," the professor answered. "And we're not 100% sure. Here in Kalos, we think that most Mega Energy comes from the legendary guardians, Xerneas and Yveltal. In other places, like Hoenn, it may come from rare-earth elements. The Giant Rock from five years ago was found in Hoenn, and it emitted enormous amounts of Mega Energy."

"Alright, but…" Madison began, wanting to contribute to the discussion also. "How does Greninja become Ash-Greninja without Mega Energy?"

"Oh, he doesn't." Sycamore smirked, looking toward the Pokémon in question, who was leaning against the wall in a corner of the room. "Somehow or other, Greninja actually generates his own Mega Energy."

"What?!" Nearly everyone in the room whirled around in unison to stare in amazement at the ninja Pokémon. He was unfazed by the attention, either having anticipated it, or simply used to being stared at in astonishment.

Prof. Sycamore chuckled. "That was my exact reaction. The first time Greninja showed up at the lab on his own to rest, our instruments started going nuts. When we finally thought to use a Mega Energy scanner, he lit it up like a Christmas tree. That was when I first started forming my own ideas about how the Bond Phenomenon works."

"Greninja…" Ash was looking at his Pokémon in awe, amazed and incredulous. "How can he do that? How is that possible?"

"Now that's the real mystery," Sycamore answered. "I've never met another Pokémon that does this. Maybe there's something in Greninja's past that caused this. He's not exactly easy to interview."

"Mairin and I have been traveling around Kalos and other regions, trying to find other common Pokémon that generate Mega Energy," Alain added. "We haven't found any so far. He's the only one."

Bonnie's amazed expression gave way to a giddy one. "That's so cool! I always knew there was something special about Greninja!"

Sycamore chuckled. "He's always been special, alright. Even back when he was a Froakie. But now we know that he's scientifically special, which is an entirely different matter. He's going to be the centerpiece of my next big paper about the Bond Phenomenon."

"Professor, how does…" Clemont started to ask another question, as the rest of the room broke into a collection of small discussions, forming a low rumble of white noise. Ash tuned out the voices around him, keeping his eyes on Greninja, who continued to stand in the corner, cool and aloof. Ash's mind was consumed with questions, as he wondered what mysteries his Pokémon held in his past.

In a calm and tranquil forest, a small blue Pokémon hobbled his way toward a pristine lake, its waters disturbed only by the school of Luvdisc swimming under its surface. He limped over to the water's edge, nearly collapsing to his knees as he leaned forward, taking a long and desperately-needed drink. He eventually sat up again, looking at the frog-like face reflected in the lake, shining in the moonlight. He could see heavy bruising on his body, and some of the bubbles on his mane missing, though the one eye that hadn't yet been swollen shut. He gave his own reflection a determined glare. Despite putting himself through one vicious battle after another, Froakie still was not satisfied, the chip on his shoulder weighing heavily on him.

It was only weeks ago that he had been given to a new trainer, by the tall and lanky scientist in the large city. They had traveled together, fought and captured other Pokémon, and battled against other trainers. Froakie had tried his best every time, attacking with as much strength as he could muster, but his opponents were much stronger than he had expected, and he lost more often than he won. The trainer looking after him grew more and more resentful as the days went on, visibly angry about the Pokémon's lack of progress. Finally, after losing a very important battle against a powerful trainer in a different city, his trainer had broken his Poké Ball in half and told him to leave, so that he could find another partner who could win him the Gym Badge he wanted, whatever that was.

Froakie was distraught, but at the same time, he was enraged, fired up, chomping at the bit. He knew how capable of a fighter he was. He could see the potential inside himself, burning like a fireball, demanding to be unleashed. He started challenging every Pokémon he came across, wanting the experience and the vindication, wanting to prove to his old trainer that he had made a mistake by letting him go, even if the human would never come to realize his error.

After dozens of difficult battles over the course of a week, however, Froakie was looking rather worse for wear. As he looked down at himself in the water, his breathing labored and shallow, he was having trouble seeing the warrior inside him through the bruises and the wounds. Soon, he was having trouble seeing anything at all, as his vision began to swim, and he fell forward into the water, passing out.

He awoke sometime later, his eyes gradually opening, watching the blurry outlines of trees as they slowly moved past him, in the darkness of the night. He quickly realized that whatever he was resting on was moving, walking him carefully through the forest. Turning his head, he was barely able to make out a chandelier of ice-blue antlers, atop the dark blue head of what appeared to be a proud and regal buck. Froakie had never seen a Pokémon like this before, though his experience was admittedly limited. Oddly, he could feel the Pokémon glowing, a sensation he didn't fully understand. It wasn't the warm glow of a fire, or the bright light of the sun, but a bizarre radiance he had never felt before, triggering senses he never knew he had.

He didn't bother trying to get up and flee, sensing no malice from this creature, and beside that, he knew he was too injured to get very far anyway. He stayed still, drifting in and out of consciousness, as the glowing Pokémon led him through the forest to a small, shallow cave. They walked in and made their way to the back, and the deer Pokémon knelt down and set Froakie on what felt like a bed of straw and leaves. It was much too dark in the cave to see, but he felt the larger Pokémon walking in small circles before lying down right next to him. He could feel the warmth of the larger body, as it slowly rose and fell with the creature's breathing, alongside the strange and ever-present glow. The warmth and the closeness were deeply comforting, and Froakie quickly fell back asleep, exhausted.

The next day, Froakie awoke to find himself alone in the cave. The glowing Pokémon was nowhere to be found, but as he looked around, he spotted a number of berries in a small pile on the straw bedding. He wasn't sure if they were placed there for him, but his growling stomach promptly drowned out his concerns. He got to his knees and limped over, sitting next to the berries and devouring them greedily. Stuffed full of food, he lay back once again and stared at the ceiling through swollen eyes, lying and resting for what felt like hours, before he felt a strange and familiar glow.

Looking toward the entrance to the cave, he saw the glowing Pokémon return, holding a concave rock in its jaws. It walked further in and set the bowl close to Froakie, who sat up and looked toward it, seeing that it was full of water. He immediately pushed himself up again, hobbling over to the water and leaning in, taking a long drink. The deer sat nearby, watching Froakie drink while grooming itself, until the frog Pokémon had his fill. He slowly tried to stand, stretching his legs, but they buckled under his weight, and he collapsed to the ground. He tried to push himself up, his arms trembling, when the deer Pokémon placed its muzzle underneath his body, lifting him up and placing him back on the bed. Froakie groaned, feeling humiliated and defeated, as the glowing Pokémon lay back down and continued to groom itself. After some time, the sun had gone down, and the deer curled up next to Froakie once again to fall asleep.

This routine continued over the next couple of weeks. The glowing Pokémon continued to bring food and water to its smaller companion, watching over him and making sure he had what he needed to heal. Froakie was improving slowly, his wounds healing and his legs recovering. Soon he was able to stand and walk on his own again, which he did at every opportunity, wanting to be well again as soon as possible. Eventually he was practicing attacks, firing off Water Pulses and Bubbles at the side of the cave, which grew stronger and stronger every day; before long, they seemed to be even stronger than they were when he was with his trainer. Even as he improved, however, the two Pokémon continued to fall asleep side by side, every night. Froakie had grown accustomed to the deer Pokémon's warmth, and even its mysterious glow proved to be comforting after so long.

One day, Froakie found himself waiting longer than usual for his companion to return. The sun was setting, and normally the glowing Pokémon had returned by now, bringing water or berries. He continued to wait nervously as the sun disappeared behind the horizon, its light replaced by that of the full moon. Eventually, he could stand the wait no longer, and he stretched his still-sore legs before walking outside, starting to look for his new friend.

After thirty minutes of scanning the forest in a widening circle, he could feel a faint but familiar sensation, the glow that he had become accustomed to. He started running toward the glow, relieved, but he screeched to a halt as he heard harsh and sinister human voices.

"You can't hide forever, Xerneas! Come on out now and save us the trouble!"

"I can't believe it! A legendary Pokémon, right where they said it'd be!"

"We're going to be gazillionaires when we capture that thing! We'll live like kings for the rest of our lives!"

Froakie began sprinting as quickly as he could, his heart dropping. He didn't know that the humans were poachers, not being familiar with the concept, but he knew from the tones of their voices that they had ill intentions toward his caretaker. He was still in pain, his stamina not as high as it could be, but it didn't matter. He would power through on pure adrenaline.

It wasn't long before he found who he was looking for. The deer Pokémon was running tiredly through the trees, looking as if it had been chased for hours. Behind it were three adult humans, each with their own powerful and menacing Pokémon. One of them Froakie recognized as a Tyranitar, having seen it while traveling with its old trainer. The second Pokémon had the appearance of a dragon, with a red head, a blue body, and jagged, sharp wings. The third Pokémon was a dark-blue toad, with a pointed horn on its head and a red patch on its stomach.

"Toxicroak, use Sludge Bomb!" one of the humans commanded. The toad Pokémon opened its mouth, generating a purple ball of gunk, which it promptly spat out at its retreating target. Froakie immediately leaped forward, forming a Water Pulse in its hands and heaving it as hard as he could. The two attacks collided in midair, bursting and falling to the ground. Everyone stopped and turned toward Froakie, who was glaring back defiantly at the attacking humans.

"Well, what do we have here? Look at this little guy, trying to play the hero! How cute!"

"Druddigon, get it with Crunch!"

Froakie watched as the red-and-blue Dragon-type Pokémon roared and charged, its jaws open, ready to deliver a powerful bite. The frog Pokémon leaped out of the way at the last minute, responding with a series of bubbles from his mouth; they hit their mark easily, causing Druddigon to stumble slightly. As he landed and prepared a Water Pulse attack, he was knocked away effortlessly by Druddigon's powerful tail, skidding to a stop a few feet ahead of the glowing Pokémon. He groaned and forced himself to his feet, in significant pain, but ready to push through it.

"Hah! This Froakie's not bad!" one of the humans taunted. "Not good enough, though!" He gritted his teeth, running forward, one of his fists glowing as he prepared a Pound attack. He leaped into the air, aiming for Druddigon's head, wanting to buy his friend time to run away.

As Froakie moved to strike, his eyes went wide as a powerful Slash attack tore through him. He felt himself flying backwards, rolling across the ground, all of his energy immediately sapped. The pain faded quickly as his body went into shock, his vision and hearing growing weaker, no longer able to feel his own extremities. He used his arms to laboriously pull himself to the front hoof of his companion, collapsing against it. If he couldn't fight off the attackers any more, he could at least use himself as a shield for a few moments longer.

He heard the muted sound of laughter as the humans approached, a sound that faded suddenly and sharply a couple of seconds later. He could no longer see what was happening, but he could feel the deer Pokémon's front leg shifting and growing, becoming stronger and more muscular. He could feel the glow becoming harsher and more intense, until the Pokémon was shining like a star, the strange energy coming off of him in waves, as if it could barely be contained. What happened next was a cacophonous mass of shaking ground and crunching sounds that lasted for nearly a full minute until it faded. When it did, the sound of the humans and their Pokémon was long gone.

Froakie clung tightly to the glowing Pokémon's leg, not knowing what else to do, barely able to see or hear, his body feeling cold. He hoped and prayed that his friend was safe, that he had somehow managed to do something to keep it from harm. He could weakly feel his caretaker's leg shrink and return to normal, before the Pokémon kneeled down and pulled him close, nuzzling him gently with its snout. As Froakie closed his eyes and reveled in the affectionate gesture, he could feel a spark of energy appearing inside him, which soon grew to massive proportions. His eyes shot open as the energy began shooting through him like electricity, spreading from his core to his fingers and toes, erasing his pain and fatigue and clearing his mind.

Both Pokémon stood at the same time, as Froakie looked down at himself with an intense curiosity. His injuries were gone, chased away along with his fatigue. His senses had grown sharp once again, perhaps sharper than they were before. He had gone from hanging by a thread to the pinnacle of health, through some mysterious magic that his companion possessed. He looked back up, gratitude and amazement all over his face, and he could see clear relief in the deer Pokémon's eyes. He watched as his friend leaned down to nuzzle him, a gesture that conveyed gratitude, affection, relief, and a hint of sorrow. Froakie returned the gesture, not entirely sure what had just happened, but knowing what was going to happen next.

As the glowing Pokémon stood up straight, it turned and began to walk away, slowly, reluctantly. Froakie's heart ached as he watched his companion leave, but he didn't fight it, understanding why. This place was no longer safe for his friend. It would have to find somewhere else to live, where more humans wouldn't be able to come and find it. Besides, Froakie knew that he would always be carrying a piece of his friend with him. He was glowing now, too, with a powerful energy that radiated out from his core, the same energy that he had been basking in for the past couple of weeks.

Once the deer Pokémon was no longer in sight, Froakie turned and walked off in the other direction, starting the long journey back to the tall scientist in the large city. He had accomplished his goal of becoming stronger, much stronger than his previous trainer had wanted him to be. Now he needed to find a new trainer, one that would appreciate how special he had become.

"Greninja?"

The Water-type Pokémon started a bit at the sound of his name being called, emerging from his memories. The visions of his past faded, replaced with the streets of Lumiose City in the light of the setting sun. He had retreated to the roof of the laboratory some time ago to reflect, and someone had finally come to join him.

He turned around to see his trainer standing behind him, the trainer that had proven himself to be strong enough to handle his Pokémon, the trainer that Greninja had chosen. He had his own faint glow to him right now, but it was weakly radiating out from his skin, not shining out of his core. Everyone who entered the scientist's lab glowed like this for a little while, with all of the Mega Energy bouncing around inside. The glow would fade in a day or two.

"Did you come up here to be alone?" Ash asked. "I can leave if you'd like…"

Greninja shook his head, turning back to the edge of the roof. His trainer smiled and walked up beside him, looking out at the streets of the city, and the people that lived there, walking and talking and laughing and smiling.

"You're itching to get back out there, aren't you?" Ash glanced over at his Pokémon, waiting for some sort of answer or reaction. Greninja didn't speak, didn't nod or shake his head to confirm or deny, but the expression on his face laid his thoughts bare.

He smiled sadly and looked back out at Lumiose City. "Yeah, I get it. This is what you've been working to protect all these years. These places, these people… Kalos needs you more than I do now. It needs its guardian." Greninja continued to stand in silence, not needing to say anything. His trainer seemed to have a sixth sense for what Pokémon were thinking and feeling, especially his own. It was one of many things that made him unique, made him special.

"Greninja…" The Pokémon looked over, seeing his trainer holding a Poké Ball in his hand. "I brought your Poké Ball here with me, just in case you would, you know… want it." The boy extended his hand nervously, offering the device to him. "If you want to be let go… be your own Pokémon again… just let me know, and-"

Greninja silenced the boy by reaching his webbed hand out, resting it on top of the device. He looked up to meet Ash's gaze, as he pushed the Poké Ball back toward his trainer, in a clear and unmistakable gesture.

A smile spread across Ash's face from one ear to the other, as he felt the tension evaporate from his chest. "Got it. I'll take good care of it, I promise." He reattached the ball to his belt. "Thanks again for everything, Greninja. It was great traveling together like we used to. I hope it's not too long before we see each other again."

His Pokémon nodded, extending his hand. Ash reached out and grasped it, giving it one good shake, before both of them stepped forward and wrapped their spare arm around the other, in the same sort of masculine hug they had exchanged upon Greninja's original departure, five years ago. Ash was still smiling as the two stepped back, pushing his sadness down inside of him.

"Take care of yourself, Greninja. It's tough out there, but so are you."

Greninja nodded again, saying goodbye in his own language before turning and leaping off the edge of the roof. He landed on the roof of the adjacent building, one story down, and started running and jumping his way deeper into Lumiose City. Ash watched him go until he was completely out of sight, before turning and making his way back inside, where his friends were waiting.

Several hours later, Ash and his friends were all asleep, as was most of Lumiose City. The six travelers were all resting in their own room in one of Lumiose City's numerous Pokémon Centers, while Clemont and Bonnie were in their own beds, in their own home. Bonnie was curled up in her bed, with Dedenne resting beside her on her pillow, while Squishy was snoozing in a makeshift bed that Bonnie had placed on her desk.

A quiet but sharp rapping sound roused Squishy from his sleep. Opening his eyes, he turned toward the window, shocked to see Greninja hanging from the side of the building, his body illuminated by the street lamps nearby. Squishy hopped out of his bed and over to the window, which the frog Pokémon carefully and quietly opened, before reaching his hand out with the palm facing up. Squishy hopped into his hand, trusting his old companion implicitly, and Greninja closed the window again before climbing up to the roof of the building, moving effortlessly even with one hand occupied.

As Squishy's eyes cleared the rooftop, he came face-to-face with an imposing white-and-purple Pokémon, hovering a foot or so above the building. Its body sported a long purple tail, spindly arms that ended in three-fingered hands, and a pair of cold, calculating eyes.

"I did not expect one of the legendary guardians of Kalos to be in the care of a ten-year-old human girl." The Pokémon spoke in a deep, emotionless male voice, projected directly into the minds of Squishy and Greninja with his psychic powers.

"I am in her comfort, not her care," Squishy responded defensively, speaking in the exact same manner. "And I don't see what business it is of yours."

The floating Pokémon let out a noise like a hmph. "You're right, it is none of my business." His eyes quickly sized up the small, green Pokémon. "So it is Zygarde that I am speaking with."

"It is." Squishy looked back, unintimidated. "Who am I speaking to now, and why?"

"I am known as Mewtwo," the other Pokémon answered. "I am here investigating matters of deep concern, and I am in need of information."

"Deep concern?" Squishy cocked his head. "Should I be concerned as well?"

"Perhaps," Mewtwo answered. "That depends on what you can tell me about the Vein Collapse."

"I see." The smaller Pokémon looked over the larger one carefully, trying to determine if this Mewtwo creature could be trusted. Eventually, he decided that answering questions likely wouldn't cause much harm, if any. "Very well. What do you wish to know?"

"Nothing, yet. We still have one more who needs to join us."

"Who is-" Squishy began, before a gust of wind blew past both of them. All three of them looked up to see a large, orange Pokémon flying overhead before turning around, coming to a landing. They turned to watch as the Charizard flapped its wings and slowly landed on the roof, snorting and looking around suspiciously at its company. It held still as a young man hopped off of its back, stepping forward and curiously studying Mewtwo, then Squishy, then Greninja.

"This has got to be the strangest meeting I've ever been a part of," Alain spoke in a nonchalant tone.

"Good, we're all here," Mewtwo responded. "Now we can begin."