|Air date||June 30, 2014|
|Written by||Rex Salazar|
The episode begins in the Hermitage, Aelita wants to speak with Anthea about the discovery of the body of Allison hid in the cupboard and she puts a bit nervous, asking an explanation why she hid it here. She answers her that she had found the supercomputer and she was about to to use it to contact to the Checkmate but she doesn't know it still and she hasn't commanded any message.
But also she confesses that she isn't the only who she killed, she poisoned the rubber of the shopping centre in the hospital. Aelita angers with her by what her own mother has done to kill two innocent people but they aren't it. Although only she did it for protecting the Lyoko-Warriors to keep out of scope to the Checkmate. Aelita sighs and asks her that she's going to do with the body of Allison and she answers that she doesn't know it still but already she will think it in another moment.
Aelita goes to Kadic not to arrive late to Physical Education with Jim that today they must play to a party of hockey. While in Kadic, Jim is organising to the students to divide them in two groups when Aelita arrives just in time and joins with the others students. It begins the party during an hour without knowing that a car is parked outside of Kadic with a blond woman with some glasses of sun, really she's the agent Chloe observing the Lyoko-Warriors.
After finishing the party, the Lyoko-Warriors go to the changing room by separate in boys and girls, Jeremy goes out of the shower and says him that today they have a mission to finish with X.A.N.A.-William and X.A.N.A.-Sissi still under control of the Checkmate and free X.A.N.A. of the shield of the guardian that he has a perfect strategy like the distraction, is to create polymorphic clones of the Lyoko-Warriors to combat against X.A.N.A.-William and X.A.N.A.-Sissi.
The true Lyoko-Warriors have to free X.A.N.A. of the shield of the guardian but they don't know what time can last the distraction. While in the changing room of girls, all have gone except Yumi and Aelita and want to speak privately about Anthea, she has confessed a very fat secret on the two murders that her mother have committed all related with the Checkmate and explains her that there is a body in the cupboard in the Hermitage and a robber was poisoned by her everything for protecting the Lyoko-Warriors.
Aelita doesn't know why she did it and Anthea can finish in the prison if the agents of the FBI investigate this murder in the hospital from the past month, which would put in danger his future and she will do the possible to protect and remain unseen in the Hermitage until it solve the of the Checkmate, without knowing that Sissi is listening the conversation who is showering and thinks the subject if it's the moment to give the letter which she had found in the library and decides to give it after the mission.
Tonight, all the Lyoko-Warriors go to the Hermitage to the old sauna but Anthea isn't and she has gone in some part without saying to where, but she checks the cupboard where found the body and no longer is. Afterwards Aelita goes to the old sauna with the other, Jeremy explains that he has activated his own tower and the polymorphic clones already are in the sector 5, William and Sissi already are in Lyoko in the ice sector expecting their arrival.
Yumi, Ulrich, Aelita and Odd enter the scanners preparing the virtualization to the ice sector and at the end they arrive together with William and Sissi finishing his wait, ask which plan has to free the guardian and says that they will combine the powers between William and Sissi with their two swords giving the energy to the maximum with the tower activated of Jeremy that can give result to the plan.
While the Lyoko-Warriors in polymorphic clones arrive running by the corridor, X.A.N.A.-William and X.A.N.A.-Sissi are waiting them and preparing the fight against them. But they don't know that William and Sissi were real together with the others clones, the clones (William and Sissi) are in the ice sector without realizing like part of his strategy.
Aelita (clone) throws continuous energy fields to X.A.N.A.-William to block with his sword absorbing the energy until arriving to her limit and Ulrich (clone) takes out the katanas with the supersprint and jumps to behind X.A.N.A.-William, he strikes back quickly with the sword like this defending. Yumi (clone) takes out the fans throwing them to X.A.N.A.-Sissi and she defends with the sword and she strikes back against Yumi when remaining without fans, acting quickly Odd (clone) shoots him laser arrows to the back of X.A.N.A.-Sissi almost weakening it temporarily.
Aelita (clone) throws continuous energy fields like the same previous to X.A.N.A.-Sissi and finishes it destroying in pieces leaving only the sword. X.A.N.A.-William uses telekinesis to attract it but Yumi (clone) uses the same telekinesis to attract one in the another with all his strengths, but X.A.N.A.-William continues defending against Ulrich (clone) of his katanas.
Odd (clone) takes advantage of to take the sword moving quickly by the telekinesis of Yumi (clone) and X.A.N.A.-William, he takes it running and jumps behind X.A.N.A.-William and nails it, but he's immune and afterwards nails him the katanas in front of X.A.N.A.-William. Suddenly X.A.N.A.-William goes out him a big shine of light in the eyes. Sissi and William (real) escape running that it will explode leaving to the clones that left it to their luck.
William and Sissi (real) run by the corridor when X.A.N.A.-William is shining the light and finishes creating a big explosion crossing by the corridor almost to them ready to be devirtualized, but are rescued by Jeremy when calling the Transport Orb with the password "SCIPIO" and it carries them just in time but the clones are destroyed. Finally X.A.N.A.-William and X.A.N.A.-Sissi are destroyed and an agent informs him to the Black King and the Black Queen that they are destroyed.
While in the ice sector, the Transport Orb lands and arrive William and Sissi (real) surprising Yumi, Ulrich, Aelita and Odd that they're the real and the others were clones, and they dispel completely. They give him the good news that X.A.N.A.-William and X.A.N.A.-Sissi are destroyed and this time won't go back (for now). Taking advantage of to destroy the guardian, William and Sissi joint the swords to create a big wave of energy aiming to the guardian and shoot to the guardian, destroying it successfully.
The spectre of X.A.N.A. is free but instead of attacking, he doesn't do at all and goes away only simply leaving the Lyoko-Warriors. X.A.N.A. arrives and possesses an agent of the White Knight. Now possessed, he arrives to the base of operations to speak with the Black King and the Black Queen but they realize that he's unde X.A.N.A.'s control. He attacks him holding him the neck, giving several blows with a fist by revenge but the juge (White Bishop) shoots him a tranquilizer dart to the neck of the agent White Knight and he sleeps unconscious.
The agent White Knight (X.A.N.A.) is locked in a special prison not to leave him escape, the juge (White Bishop) asks to the Black King what will do with him but for the moment keep it locked until thinking a way to send it back to Lyoko. The Lyoko-Warriors finish the mission successfully but with X.A.N.A. free surely will be looking for revenge against the Checkmate.
Sissi speaks with Aelita and she wants to speak in her room, when arriving in her room a while afterwards she gives him a letter that belongs to Franz Hopper and leaves it to Aelita to alone reading the letter (without revealing). Then somebody enters in Sissi's room, revealing that it she's the agent Chloe that detains Aelita in the act. While in the living room of the Hermitage, Jeremy with the tablet says him that today it has gone out a trailer of the new film of X-Men teaching it to Yumi, Odd, Ulrich and William and Yumi appears in that film which will be released on April 21 in the cinemas.