Code Lyoko — Episode 4: False Lead

You are watching the episode False Lead When Xana hacks into a weapon's manufacturing computer network and leaves a paper trail pointing to Jeremie, government agents arrive at the school looking for him. Then, the whole gang arrive at the factory. When they end up tracking Jeremie to the factory, Xana possesses them for an attack on the supercomputer itself in The Ice Sector, and in The Mountain Sector.