On chapter four where Jimmy and Korra travels through time.

REMINDER: I DO NOT OWN JIMMY NEUTRON, AVATAR OR ANY OF THE CHARACTERS.

Three years ago to the past before Harmonic Convergence of 171 AG started, at the police headquarters, light shined in two lockers. Korra, Jimmy, and Goddard struggled in the locker.

"Ohh, I thought it could just transport us outside." Korra efforted before Goddard barked. "You can say that again."

"Sorry." Jimmy said before he, the Avatar and robot dog managed to exits the locker.

"Whoo, nice time travel." Korra said sarcastically. "Ouch, I had more room in my hip. Why are we at the police headquarters?"

"According to the date, we're right at three years, and days before Harmonic Convergence started." Jimmy said looking at the date on Goddard's screen.

"Ok, good. Let's get outta here before someone sees us." Korra said before she, Jimmy and Goddard walked quietly to avoid being seen.

In another locker, Raiko banged three times before he could get out of there.

"I'm actually in the past. This boy is a genius." Raiko said fascinated. "Now, I need a disguise so my past self doesn't suspected me from the future."

Korra, Jimmy and Goddard sneaks out to the office without being seen by anyone. Korra gasped when she sees the Mako of the past.

"There's Mako. This is the part when I come in." she whispered.

The past Korra kicked the door open.

"Duck!" Jimmy whispered before he, Goddard and Korra hide behind a table. Korra looked at her past self, angry at Mako's past self.

"There's me. I remember this breakup." Korra said, remembering her breakup with Mako.

"You ratted me out to the President?" Past Korra asked agitatedly.

"Korra, let me explain." Past Mako said calmly.

"Explain why my boyfriend stabbed me in the back?" Past Korra asked bluntly.

"Look, the President of the Republic asked me a direct question. What was I supposed to do?"

"You betrayed me, and my family!" Past Korra yelled angrily and accusingly before she kicks Past Mako's desk aside with airbending.

Goddard was surprised. "Damn." he said with Ice Cube's voice.

"Enough! Look, I have a job to do! I can't constantly be worrying about keeping you from making another huge mistake!" Past Mako snapped.

"Well, I have a job to do too, only it seems like you're always standing in the way of me getting it done!" Past Korra yelled back angrily while Raiko quickly sneaked out from the office without being seen.

"Well, I guess if we're both putting our jobs first, maybe there's no room for our relationship!"

Korra and Mako's past selves both looked at each other in silence while Korra, Jimmy and Goddard sneaked out of the office.

"Come on, come on, come on, come on, come on." Jimmy whispered until they've finally got out.

"So, what? Are you breaking up with me?" Past Korra asked sadly.

"Yeah. I guess I am." Past Mako answered sadly before a tearful Korra of the past runs out of the office.

Past Lin exits her office in shock. " What the flamey-o happened here?"

"I broke up with the Avatar." Past Mako said sadly.

"You got off easy. You shoulda seen Air Temple Island after Tenzin broke up with me."

Outside headquarters, Korra, Jimmy and Goddard ran out from the building.

"Phew! I would have drop dead if I see me." Korra said before she sees her past self. "Oh…"

She, Jimmy and Goddard hide against the wall before Korra's past self runs out crying.

"I remember crying over that breakup. It was… Hold on. She's going to the harbour, to get a boat to the Fire Nation for help against Unalaq." Korra said.

Jimmy pressed his watch before a screen was on. Jimmy and Korra's friends were there. "Are you watching the past?"

"Watching like an eagle, Jimmy!" Sheen saluted.

"Good, keep watching for some changes while we find the Shadowbender." Jimmy said before he turned off his screen. "We gotta warn her about him."

"Oh, what? Tell me that we're from the future? Good thinking. She'll just think we're spirits, and working for Unalaq, Jimmy. How can we warn me with her seeing my face?"

"Goddard, hat, trench coat." Jimmy ordered before Goddard gives Korra a hat and trench coat.

"Thanks, Goddard." Korra said gratitude. "That'll work."

"Let's go catch up on you. Uh, her… Whatever. Gotta blast." Jimmy said before he, Goddard and Korra runs to the Avatar of the past.

Meanwhile, a man in a suit was standing near the boat the past Korra needed to go to the Fire Nation to ask them to save the Southern Water Tribe. He checked his watch to meet the Korra of the past.

"Hm, she should be here any second now." he said before he sees Past Korra running. "Good evening, Avatar Korra."

"Good evening, sir." Past Korra said crying, rubbing her tears off. "Look, if you want any help from me, but I'm on an important mission."

"And that's why I'm here to help you for, my dear. Dr. Hun, man of science, archology, and history." the man introduced himself. "I know what Unalaq is up to."

Past Korra knew her uncle was planning something, though, in the future, Unalaq was going to free Vaatu.

"Ok, take your time. What is he planning, Doc?" she asked concernedly.

"Let's start with the origin of the Avatar. A human named Wan was banished from his village for a rise of rebellion. But he was gifted with firebending by the Fire Lion Turtle. He met the two ancient spirits of all. Raava, the Spirit of Light and Harmony. And Vaatu, the Spirit of Darkness and Chaos. They are destined to fight each other on Harmonic Convergence of 9,829 BG. But they cannot completely destroy each other. One cannot exist without the other. Even if Raava defeats Vaatu in this encounter, darkness will grow inside me until he emerges again. And if Vaatu defeats Raava, light will grow inside until she emerges."

Past Korra was astonished by Dr. Hun's story of Avatar Wan. "How does that have to do with the Avatar Cycle?"

"When Wan gained the bending of air, earth and water from the other Lion Turtles, he fused with Raava during the last Harmonic Convergence and became the Avatar. He defeated Vaatu, locked in in the Tree of Time for ten thousand years of imprisonment. I've learned that Unalaq is going to free Vaatu as long as the two spirit portals are open."

"He is?" Past Korra was shocked. "Why?"

"The same way Wan did with Raava, he's going to fuse with Vaatu to become a Dark Avatar, and bring ten, thousand years of darkness to the world." Hun answered.

"He tricked me! I never should have opened that spirit portal. There's gotta be a way to stop him." Past Korra said.

"Yes, closing the spirit portal during the next Harmonic Convergence can prevent Vaatu from being free from his prison. Or…"

"Or what?" Past Korra asked.

"If it's too late, Vaatu would be free, and the Dark Avatar Cycle will start. There might be a price to stop him. And you wouldn't try that." Hun said before turning around.

"I can take that risk." Past Korra determined. "What do I have to do?"

"In my theory, what if… you merge with Vaatu?" Dr. Hun asked while grinning.

Past Korra was shocked. "Me? fusing with him? The Avatar only had one Avatar Spirit."

"Think about it. If you fuse with Vaatu, he will be trapped within you forever, he won't control you. With Raava and Vaatu inside you, you'll evolve into a greater Avatar, stronger than before. Unless you let Unalaq become the embodiment of darkness and chaos, let that fool Raiko, and your ex-boyfriend stop you from taking that risk."

Past Korra shed a tear, knowing that the past Raiko refused to send the United Forces to the South for aid, and Mako betraying her and breaking up with her. She looked at the scientist with a determined face.

"I'll do it."

"Excellent!" Dr. Hun clapped his hands to beckon a bison. "If you wished to close the spirit portal, go the Eastern Air Temple for Tenzin's help to enter the Spirit World. Leave the asking for help to me."

"Thank you, Dr. Hun." Past Korra said before she hopped on the bison. "How would you convince them to help me?"

"I have a gift to offer some help. Good luck, Korra." Dr. Hun said before Korra's bison flies off to the Eastern Air Temple.

Korra, Jimmy and Goddard looked up to Past Korra flying above. Korra never seen something different in her past.

"I was supposed to be on a boat to the Fire Nation. Desna and Eska tried to adapt me, a dark spirit attacked me, and I lost my memory. But this. This never happened before."

"There!" Jimmy pointed at Dr. Hun. "That must be the Shadowbender!"

Dr. Hun looked at Jimmy, Goddard and Korra and he returned to his true form as the Shadowbender.

"Jimmy! It's good to see you! it's been a day since my creation. I dig what you gave me, great superpowers, and intelligence. UnaVaatu's face and form, even their memories. I considered you like my dad, but I know you made a mistake creating an evil monster, so I just accepted it. Love's not my thing, hate it so much. Now, what you doin' here in the past, come to stop me?"

"You got that right, Shadowbender. Whatever you're planning to do with the past, we won't let you mess it up." Jimmy determined.

"You're too late to stop me, Jimbo." Shadowbender said. "I've change time. What happened to Korra when losing her memory never happened. Soon, everything will be in my image."

"Oh, yeah? Well, let's see about that." Korra said.

"Goddard, battle armour!" Jimmy shouted before Goddard morphed his panel.

Jimmy pressed the button to teleport his robotic battle armour from the future and he and Goddard went in. The trio faced the ooze villain to a fight.

"Oh, y'all gonna go all science and bending on me, eh?" the Shadowbender asked teasingly before he blasted his ooze to Jimmy and the Avatar, but they've dodged the attack.

Korra suddenly bends a water bullet from the ocean. The Shadowbender stopped the water easily with one hand and absorbed it and shoots it right back at Korra.

"Oh, yeah, I'm bad!" Shadowbender said before he was knocked down by Jimmy.

"Nice shot, Neutron." Korra said with a smirk. "Now let's beat the hell outta him."

Korra hits Shadowbender against the head with a back spinning kick, due to which she slammed his head against the golden ornament on a Satomobile.

"Don't. Hit. The. Face!" Shadowbender yelled before he threw his ball of ooze at Korra's head.

Jimmy tried to strike the Shadowbender, but he melted down and glided away until he raised up and bashed the armour down. Korra managed to break free from the ooze before the Shadowbender charges Korra by jumping up. However, before he could land and attack, she catapulted him high into the air. Jimmy tried to shoot the Shadowbender, but he managed to escape, and the blast shoot at a building before it went down.

Jimmy was worried. "Oops."

"Now, you're paying for that." Shadowbender said scornfully before he morphed his hands into hammers and knocked Jimmy down.

Korra was about to attack, but she felt a pain. Something was happening to the Avatar.

"Your time is changing, Korra, there's nothing you can do about it." The Shadowbender said evilly before laughing and melted down the drains to escape.

Jimmy regained consciousness and saw Korra panting in pain.

"Korra, are you ok?" he asked worriedly.

"I'm fine. But something's happening." Korra said before she looks back and notices her cousins' past selves were attacking her with waterbending. "Uh-oh."

"You ruined my wedding!" Past Eska yelled.

Past Eska throws a stream at Korra and Jimmy, but they manage to dodge it. She throws a rock at the twins, but they dodged and soon catch up with her.

"They think you're your past self." Jimmy said.

"I know." Korra said.

"No one steals my Bolin!" Past Eska shouts.

Past Eska hits Korra with a block of ice. Jimmy attacks Korra's cousins with by bashing them, while avoiding their waterbending attacks.

"Who are you?" Past Desna demanded.

"My friends call me Jimmy. But you can call me Neutron. James Isaac Neutron." Jimmy introduced himself to the twins.

"I'll remember that name in your grave." Eska sneered.

Past Eska manages to knock Jimmy off, but Jimmy regains her balance. Korra created a vortex with airbending and sucked them in before Past Eska threw a sharp ice at Korra's arm, slicing her before her vortex stopped.

Korra quickly tried bend a water dome, to trap her cousins, but Past Eska and Desna jumped back to their jet skis to escape.

"This isn't over, Avatar Korra!" Past Desna shouted.

"We'll get you next time. And you as well, James Neutron!" Past Eska vowed before she and her brother sailed back to the Southern Water Tribe.

Jimmy and Goddard gets off the battle armour while Goddard barked and licked Jimmy.

"Yeah, boy, we scared them off." Jimmy said.

"This isn't what it was supposed to be." Korra said concerned. "They were supposed to attack me at the Mo Ce Sea. The Shadowbender's done something that altered the timeline."

Jimmy picked up a picture of Korra sharing a kiss with Asami. Then the picture faded, like it never happened.

"Erased from existence." Jimmy realized the space time continuum had proven to be possible. "Korra, where you would you be heading for…"

Jimmy was interrupted when the police officers arrived.

"You two are under arrest." one of the officers said.

Korra was stunned. "What? For what? What did we do?"

"Uh, maybe this?" Jimmy answered nervously before he points out to the damaged street.

Korra was felling awkward. "Oh. We're in big trouble now."

The Shadowbender is changing the past, present, and future! Will this nightmare ever end?!

Next chapter will come.