One day four students found a super computer in an abandoned factory. There they met Aelita who was the guardian of Lyoko. So when ever the super virus X.A.N.A. plans an attacks, Yumi, Ulrich, and Odd go to Lyoko and protect Aelita for her to go to the towers XANA activated. So she'll be able to stop his attack and go back in time. They have to keep up with their school work and his attacks for just students. X.A.N.A. can come up with the biggest and sometimes treacherous way to destroy our heroes or the world, especially with the help of some of his monsters.

Theme Song: "World Without Danger"
Here we are
Going far
To save all that we love.

If we give
What we've got
We will make it through.

Here were are
like a star
Shining bright on your world -

Today!

Make evil go away!

Code Lyoko - we reset it all
Code Lyoko - be there when you call
Code Lyoko - we will stand real tall.
Code Lyoko - stronger after all.