Code Lyoko

A group of students uncover a parallel universe called Lyoko inside a super-computer that is threatened by a renegade program named XANA that could destroy the world. It's up to four boarding school students named Jeremy, Yumi, Ulrich, and Odd to help a humanoid being inside Lyoko named Aelita to stop the rogue program X.A.N.A and his plans to attack their world.