In the monastery, young Dragon blocks a Vermillion Warrior's sword before kicking it, causing it to come apart. "Seize the leader." Machia said as Raggmunk, Blunck and a few more warriors land near him.
Dragon quickly blocks all their swords before forcing them back, blocks Blunck's sword before knocking him aside, jabs Raggmunk, kneels down as a warrior came at him before he got up, sending the warrior over his back and does Spinjitzu, knocking two warriors into the wall and they come apart. He quickly turned to block another warrior's sword before it forces him to lower his staff and kicks him near a support. As the warriors surround him, fire and water suddenly hit them and they break apart. He looked up to the roof to see that it was Kai and Nya, both wearing their hoods so that he doesn't see their faces. "Ray." He said. "Maya. You've returned."
"Yes." Kai replied, imitating his father. "And we've, um, studied these warriors. To defeat them you cannot allow them to reform." He then turned to Nya. "You're right, he thinks we're our parents." He whispered.
"We must work together." Nya said, imitating her mother. "All of us."
Oni soon came up next to Dragon. "I thought the forging of the Time Blades exhausted you." He said.
"Uh, we rested and-" Kai imitates his father before noticing something. "Look out!" All the warriors they took down start reforming and came up behind the Elemental Masters. Dr. Hall and Consuela quickly block their attacks as Kai and Nya jump down from the roof to see them run away as the other warriors start flooding in. "Use your powers to separate them!" They charge at the warriors, kicking some down before Kai uses his Fire power on one. "Follow our lead."
The Elemental Master of Ice blocks one warrior's sword as he looked at Kai. "Keep them separated." He said. "Got it." He forces it back as Dr. Hall held out his hands to attract the metal from it and the warrior Libby was fighting while Shade's mother disappears and reappears near Blunck and Raggmunk. As two warriors charge at her, Consuela sees them and fires a shot of web at one each before pulling them back, separating them before the Master of Ice fires his Ice attack on the snakes before Libby fired her Lightning attack at them.
By the Iron Doom, Krux and Acronix look on in disappointment as there were less warriors than expected. "We're losing." Krux said.
"Well, only insofar as they are winning." Raggmunk replied as he came up next to them.
"Eh, temporary setback." Blunck said, coming up to them.
"We did not travel across decades to suffer temporary setbacks." Acronix replied. He then looked at Krux, who nods before they grab hold of their helmets, breaking them apart. They soon put the helmets on themselves.
"I was wondering when you would finally tire of their incompetence." Machia said as she came up to them.
"We always knew the time would come." Krux replied.
"So, shall I reorganize the troops?"
"Oh, I'm afraid we won't be needing your services either."
Machia soon became shocked at the news. "Supreme Commander Machia, you are relieved." Acronix said as they grab hold of her armour.
"You sons of bi-!" She was cut off when they pull her armour off and she comes apart as well before they head into the Iron Doom.
At the monastery, Kai, Nya, Dragon, Oni and the Masters back away a bit. "On my count." Kai said, still imitating his father. "3, 2-" The Vermillion Warriors suddenly fall apart. "What?"
"Why did they stop?" Dr. Hall asked.
They soon looked up to see the Iron Doom move. "All snakes: Cease battle." Krux said aloud.
"Return to the Iron Doom." Acronix said aloud. They then looked down at the snakes as they head to the Iron Doom, moving around it before heading in random parts. "Iron Doom, arise!"
"Yes, Master!" The Iron Doom suddenly spoke as it soon moved its arms up and looked at the sky before looking down at the Elemental Masters.
"It is time to rule!" Krux said as the Iron Doom raised an arm.
Libby then groaned. "Seriously?" She asked. "Normal snake samurai are hard enough. How the hell do we stop that?"
Dragon then turned to Kai and Nya. "You know this enemy." He said. "What do we do?"
"I...I have no idea." Kai replied, still imitating his father as he turned to him. He then looked back to see the Iron Doom preparing to strike before they quickly move out of the way.
"Then we must improvise." The Iron Doom then opened its mouth and fires a Vermillion egg, knocking them all back again. Libby, Consuela, Dr. Hall and the Master of Ice try to fire their attacks, but the Iron Doom isn't fazed before knocking them into a wall and moves back, letting them land on their chests. Nya then uses her Water power, but the Iron Doom then fired another Vermillion egg, causing her, Powder's mother and several other Elemental Masters to move out of the way. The Iron Doom then moves forward, breaking the gates apart, as it moved over to the Elemental Masters while they backed away. "Spinjitzu. It's our last hope."
"Ninjago!" Dragon and Oni yelled, doing Spinjitzu as they came over to the Iron Doom. It sees them before it strikes them, knocking them down as they stopped.
"It's so big it just towers over us." Nya said to Kai.
"Then let's get above it." Kai replied.
"Ninjago!" They both yelled as they did Airjitzu. The Iron Doom tilts back before grabbing them and throws them aside, down the monastery steps.
It soon picks up Dragon and brings him up to Krux and Acronix. "A futile effort." Krux said as Dragon tried to get free. "Here are the terms of surrender: Yield now, and we will destroy the Elemental Masters, but spare the citizens of Ninjago."
"But... But-" Dragon is then cut off.
"Refuse, and we still destroy you, but the citizens will not be spared." Acronix said.
Dragon soon sighed. "Do you yield?" Krux asked.
Dragon soon spat at Krux's face. "Never." He said.
"Have it your way then." He then has Iron Doom turn to a nearby village and it opens its mouth.
"Wait!" He exhales a bit. "I... I yield."
"No." Present Dragon said as he, Kai and Nya looked on. "Krux and Acronix just altered the outcome of a key battle in Ninjago history."
"Change anything, change everything." Kai said, quoting what Dragon told him.
Present
A blimp in the sky suddenly disappeared as skyscrapers start fading away. "Guys, something's really wrong." Jay said as they all look on to see a temple and some buildings replacing the city. Ray's hair was noticeably turning to grey and was too weak to look, and Blake and Samurai X were no longer there.
"The city is... different." Gewuji replied.
"Yeah." Cole said. "It looks old."
"Like Ninjago 40 years ago." Maggie replied.
"Huh?" Cyrus asked before looking at his wrist. "My BorgWatch has disappeared." He said.
"Hey, Blake's gone too." Geoff said, looking around.
"What is going on?" Jay asked.
"My worst fear has come true." Ray replied, sounding like an old man as he and Maya came up to them. "The past has been changed." He then turned to Cyrus. "Your watch doesn't exist because technology no longer happened. No computers. No telephones. No cloning. No-"
"Zane." Lloyd cuts him off when they all look to see where Zane was and head over there. What replaced Zane was his original, inactive body, wearing just a white shirt, white pants and black loafers.
Over 40 Years Earlier
The Elemental Masters look on as the Iron Doom held the defeated young Dragon before they fling him to them and they catch him. "What do we do?" Nya asked as they look on from halfway down the stairs. "The Iron Doom is just too strong. Not even the entire Elemental Alliance could stop that thing."
"I know." Kai replied. "I know." He tries to think of something. "Unless..."
"Unless?"
"Remember how we worked together at the Boiling Sea?" He soon gets out the Dragon Blade. "I think it's time to bring back the big guy." He soon ignites his hand.
"How do you know it isn't 'the big girl'?"
Back at the monastery, the Iron Doom looks down at the Elemental Masters before moving down to them. "Who do we destroy first?" Acronix asked. "Garmadon or Wu?"
The sound of the Fusion Dragon's roar was soon heard as they look to see it coming to them. "I think we have bigger issues." Krux replied, concerned. The Fusion Dragon flies in the air as the Iron Doom turns to it and the Time Twins look on, in shock. "Evasive Maneu-"
He was cut off when the Fusion Dragon struck the Iron Doom before it moves away as it tried to strike the dragon and circles around it. "We gotta get that Reversal Blade." Kai said as he and Nya flew on the Fusion Dragon.
The dragon then comes to the Apparatus on the Iron Doom and tries to grab the Reversal Time Blade, but moves away as the Iron Doom pulled out a sword from its back and tried to strike it, but missed as it flew away. "It appears that even the mighty can still fall." Oni said as he helped his brother up.
"Then perhaps there is still hope." Young Dragon replied. "Krux and Acronix's overconfidence just might be their undoing." The Iron Doom, apparently hearing them, turned to them and roared.
"This time, let's go in low." Kai said as they look on.
"Got it." Nya replied as the Fusion Dragon charges at the Iron Doom. "Yeah!"
It looks at the Fusion Dragon and soon struck it, sending it away from the monastery before they regain control of the dragon. "That's okay. Low. Bad call. That's on me. This time we hit it high." The Fusion Dragon prepares to charge at the Iron Doom again.
"Fire and Water are nearly as awful as their little brats, Kai and Nya." Acronix said from inside the Iron Doom.
"Don't you recognize the Fusion Dragon?" Krux asked. "Those are their little brats. Maximum barrage."
The Iron Doom then turned to the Fusion Dragon. "Maximum barrage engaged." It said before firing Vermillion eggs at it.
The Fusion Dragon flies around the eggs to avoid getting hit. "Eggs?" Kai asked. "They're getting desperate."
"Actually, at this speed, our skulls will crack before those shells do." Nya replied.
"Let's take 'em out." They stand up and fire their Elemental attacks at the Iron Doom, knocking it back and sending Krux and Acronix falling back.
"You know what they say: 'Fight fire with time.'" Acronix said from inside the Iron Doom.
"I hate when you make up sayings." Krux replied.
"Fine. Then how about...?" He then placed his hands on his helmet. "Iron Doom, full temporal energy."
"Full temporal energy." Iron Doom said as the Time Blades on the Apparatus start to spin.
"I don't know how much longer Dragon is gonna last." Nya said, looking down at Dragon as they stood up.
"We have to get that Reversal Blade." Kai replied.
"You're right."
"Whoa. The dragon takes both of us."
"Sorry, but you're gonna have to do it alone. I need you to buy me time."
"For what?"
"Just trust me!" She then immediately jumped off the Fusion Dragon, firing a flow of water to softened her landing. She then looked up to see the Iron Doom about to fire at her, but she runs off in the opposite direction, down the steps as the effect of the Slow Time Blade only hits the tree that Dragon was leaning on.
In the sky, the Fusion Dragon starts to fade as Kai struggles to control it. "Steady, girl. I need you more than ever." It soon returns to normal.
At the bottom of the mountain, Nya jumps off a big rock as she soon saw something while removing her hood. "There it is."
Back in the sky, the Fusion Dragon flies around as Kai fires fireballs at the Iron Doom, briefly knocking it back as the Elemental Masters see it. "Distract him." Young Dragon said and the Elemental Masters immediately fire their Elemental Powers at the Iron Doom. It turns to them and fires a Vermillion egg, knocking them all down.
Behind it, the Fusion Dragon flies down to it as the Iron Doom sees it come before it strikes it, knocking it at the edge of the monastery, damaging part of it and making the Iron Doom lose its swords. Krux and Acronix scream at the sight of the height before putting their hands on their helmets to have the Iron Doom stand. "Kai and Nya have interfered for the last time." Krux said as they look on from inside. "I will destroy them, if I have to do it with my bare hands."
"We still have the Iron Doom." Acronix replied. "We can go anywhere in time we please. If the fight is too difficult here, let's go to a time where we are sure of victory. A time where those two do not exist."
"Ah, yes. Further back in the past."
"No. Far into the future." He then placed his hands on his helmet.
The Apparatus on the Iron Doom starts to spin again and fires a Time Hole into the sky. The Elemental Masters look on it starts to head into it as the Fusion Dragon flies over to it. Kai struggles as he tries to turn it. "Hold together." He said to the Fusion Dragon. "They're getting away."
Acronix sticks his head out of the cockpit to see the Fusion Dragon and gets cross as it prepares to come close. "Head fake." He said.
The Iron Doom quickly tilts down, causing the Fusion Dragon to pass by it. "No!" The Fusion Dragon soon dispersed and Kai lands on the bridge. He then looked up to see the Iron Doom head into the Time Hole before it closes and disappeared. "No!" He then stood up while taking off his hood. "They... They got away." He shook his head, in disappointment as Nya came over to him.
"Kai?" She asked.
"I've failed everyone." He turns to his sister. "You. Mom. Dad. And Master Wu." He then lowered his head.
"Failure is often temporary, Kai." Present Dragon's voice was heard as he turned to see he was back to normal. The beard was back to the same normal height and he was no longer feeling weak. "It can be corrected. And with effort, it can even be reversed."
"Master Wu? You're-"
"Cured of the Time Punch. Thanks to you and Nya."
"And the Reversal Blade." Nya said, getting out the current Reversal Time Blade.
"But how'd you get it?" Kai asked. "Where?"
"Remember what Mom told us back at the swamp? How shortly after Acronix and Krux disappeared, she and Dad found the Reversal Blade?"
"Right. In the woods near the Monastery. But she said they sunk it in the Boiling Sea."
"We are in the past." Dragon reminds him. "It hasn't been put in the Boiling Sea yet."
"So it was still in the woods." Nya said.
"That's fantastic." Kai replied before sighing. "Krux and Acronix got away. And we can't follow them. We're stuck here forever."
"Those who don't learn from the future are doomed to repeat the past." Dragon said as he took the Reversal Time Blade. "Over 40 years from now, I will err by trying to win a fight on my own. Fortunately, we can correct this mistake because..."
Kai soon realizes what he was talking about. "We still have time."
"Yes. Focus." He held it out as Kai and Nya held the tips and they all hum. It soon starts to glow. "Nya." He lets go of it. "Release! Release!" Nya lets go as Kai suddenly floats with the Reversal Time Blade still in his hand.