|Straight to Heart|
|Air Date (US)||October 4th, 2006|
|Air Date (France)||September 9th, 2006|
|Written by||Françoise Charpiat|
|Storyboard by|| Paul Beneteau|
Alain le Dong
|Preceeded by|| X.A.N.A. Awakens: Part 2 (production)|
The Key (chronological)
|Followed by||Lyoko Minus One|
A new school year begins. Back from their relatively quiet two-week summer vacation, Lyoko Warriors quickly find themselves back at war with X.A.N.A.. The diabolical, rogue artificial intelligence who has made its way into the World Wide Web has raised the stakes with a new strategy of attack: wipe Lyoko off the digital map by destroying a huge transparent, white sphere, which located in a yet undiscovered chamber in Secter 5 directly below the arena. In effect, to rip out the very heart of the virtual world itself!
Meanwhile, Odd finds to his dismay that he is not in the same class as Jeremy, Ulrich and Aelita. But Odd also stumbles across a little-known tidbit of historical information from Jim’s past that might help him out: Jim once starred in a disco dance film, and the gym teacher doesn’t want the students at Kadic Academy to find out. Armed with this secret, Odd decides to blackmail Jim to get himself reassigned into his friends’ class, only to claim that "blackmail's not his style", guilting Jim into helping Odd get into his friends' class. Meanwhile, Yumi claims that she and Ulrich should stay "just friends and that's all" on a strictly platonic level of friendship, which Ulrich doesn't take well.
- The original French name for this episode is Droit au cœur.
- After this episode, Aelita no longer requires materialization program to materialize on Earth, since she is revealed to be fully human. As another result, Aelita develops an incredibly strong weapon of her own: small deep pink-colored, electric energy orbs called "energy fields."
- At the start of the episode Yumi and Aelita are seen playing a game of "Go", a Middle Eastern board game thought to be over two thousand years old. Aelita is seen to be winning by 6 1/2 points.