Hécatombe

A mission to gather more intelligence on Aelita's mother, Anthea, is cancelled when XANA launches another attack in the Mountain Sector. Unable to warn Odd and Ulrich, the two boys become the targets of XANA's attacks. Caught in the trap, Odd loses all of his codes once again. Meanwhile Aelita and Yumi are pinned in the Cortex by XANA's forces on route to deactivate the tower, and Yumi is later devirtualized.

On Earth, XANA has stolen Ulrich's codes as well. Realizing that Yumi is on Earth too, XANA sends the specter to find and recover the codes. After locating Ulrich and co-ordinating with Odd, Odd is sent to provide William and Aelita with backup while Ulrich locates and escorts Yumi to the factory. After arguing with Jeremy over Yumi's safety, William devirtualizes himself in order to find her. Odd goes to Lyoko while Aelita is being perused by Kongers in the Digital Sea. After Ulrich calls Yumi to find where she is, she's spotted by the specter. William and Ulrich team up to go look for Yumi, but split up after finding her phone, but not her. While in Lyoko, Odd is pinned down and out of ammunition, the Bloks are pushing him towards the Digital Sea. Aelita shows up in the Skid and destroys all the monsters.

Yumi is attacked by the specter, but rescued by Ulrich. After deactivating the tower, it is revealed that XANA has regained 95% of its power. Keeping the promise, it is decided that the virus that Jeremy, Laura, and Aelita have been working on will now be used for destroying Tyron's supercomputer, and preventing any further communication with Anthea.

Next episode

S01E26 - Ultime mission