Return to the Past

Return to the Past
First appearance	X.A.N.A. Awakens (chronological-wise) Teddygozilla (production-wise)
Purpose	Returning to the past, erasing memories
Creator(s)	Franz Hopper

Time reversion, also known as, "Return to the past, now!", is one of the greatest and most useful properties of the Supercomputer. It allows the user to return to a point in time of their choosing. Just how far back it can go is unknown, but it seems to be limited to a maximum of roughly two days. In addition, each return trip doubles the processing power of the supercomputer, which in turn doubles X.A.N.A.'s potential power in seasons one and two.

Use

The person at the Factory Interface usually activates a time reversion after an attack to erase any damage caused and memory of the events that transpired. The people who have been scanned into the Supercomputer usually remember everything that happened of the previous timeline. However, time reversions don't affect events or beings that are linked to Lyoko, undo possession, or deactivate Towers. Also, it cannot bring the dead back to life. Its power must be based on physical alteration, manipulating every object, force, and living thing in range to a past state, and interfering with people's brains to revert their memories too, but restoring a life that has already died seems beyond its capability.

The return to the past program was used more sparingly after the episode A Great Day, when X.A.N.A. constantly rewinds the same Tuesday over and over to increase his power, leaving the Lyoko Warriors in a pinch. Also, since Aelita was still not fully human at that time, she was still stuck on Lyoko when a time return was launched.

Also, time reversions can be very dangerous, as Jeremie used it with the head set that multiplied his intellect by 10 every time he used it, it caused him serious brain damage. The design concept of this headset was created by Franz Hopper, Aelita's father.

The characters in the show have used the time reversion to their own personal gain: Ulrich used it to win the lottery in a misguided attempt to prevent Yumi from moving back to Japan, which got him banished from the group temporarily (The Chips Are Down) and Franz Hopper used this feature 2546 times over the course of his research, becoming more and more mentally unstable with each time reversion.

Jeremie is usually the one that activates the time reversion process, though all the other members of the team are shown to be capable of activating it as well.

From the third season onwards, since X.A.N.A. had escaped from the supercomputer and didn't power up with it anymore, Jeremie seemed more relaxed about returning to the past even though sometimes it wasn't needed like in the first season.

During Code Lyoko Evolution, it is revealed that Laura Gauthier modified the boundaries of the Return to the Past program during the episode Virus without Jeremie's knowledge to include herself to be unaffected by the memory loss effect. This seems to be the only alternative to remember events after a time reversion which doesn't include the subject to be materialized into the Supercomputer. It was also revealed that the event can be specifically altered to erase Lyoko Warriors memories as well by focusing it solely on the targeted warrior, if they would be too much of an risk for other group. This was done by Jeremie to Laura, who lost completely every memory she had about Lyoko Warriors and their fight against X.A.N.A and Professor Tyron after she launched a preemptive attempt to destroy X.A.N.A. that nearly got William turned into X.A.N.A.'s slave again.

Times when Used

Season One

• Every Episode (except for Frontier and Code: Earth)

Season Two

• New Order
• Exploration
• A Great Day
• Final Mix
• The Chips Are Down
• Temptation
• A Bad Turn
• Attack of the Zombies
• Ultimatum
• Vertigo
• Cold War
• Is Anybody Out There?

Season Three

• Tidal Wave
• False Lead
• The Pretender
• The Secret
• Temporary Insanity
• Triple Trouble

Season Four

• Double Take
• Opening Act
• Wreck Room
• Hot Shower
• The Lake
• A Lack of Goodwill
• Guided Missile
• Canine Conundrum
• Cousins Once Removed
• Music to Soothe the Savage Beast
• Wrong Exposure
• Bad Connection
• Echoes

Season Five: Evolution

• Mrs. Einstein
• An Assured Professional Future
• False Pretenses
• Mutiny
• Temporal Paradox

Immune Entities

Some people are immune to the return trip. This can be achieved by being run by the supercomputer, or being recognized by the supercomputer as someone to not wipe. The following individuals are immune:

Person	Status
Jeremie Belpois	Gained in X.A.N.A. Awakens
Odd Della Robbia	Gained in X.A.N.A. Awakens
Ulrich Stern	Gained in X.A.N.A. Awakens
Yumi Ishiyama	Gained in X.A.N.A. Awakens
Aelita Schaeffer	Gained sometime in 1994.
Waldo Schaeffer	Gained, presumably, on first use.
X.A.N.A.	Gained, presumably, on first use.
William Dunbar	Gained in Final Round, though pieces of it bled through earlier.
William Clone	Assumed, since he was shown remembering behavior from an alternate timeline in A Lack of Goodwill
Monsters	Inherit to the system
Laura Gauthier	Gained in Virus, and lost in Mutiny.

Gallery

The program is activated on the Factory Interface.

The Factory with the white light appearing behind it.

Temporal Reversion in Mrs. Einstein

Returning to the past at night.

Being activated in Evolution.

A bright light illuminates the Factory floor.

Kadic, with the sphere of light covering the building.

Time reverse at the Hermitage.

The program starts up!

At Kadic during the day.