Code Lyoko - The Blue Elf

This is a story about Kya Schaeffer. After the destruction of XANA, Aelita starts to see strange memories. They are the same as her old ones, but a blue-haired girl is starting to appear in them. Aelita asks Jeremie if he can take her to see the factory once more to make sure nothing is wrong, Jeremie accepts only due to his feelings and hoping she will be proved wrong and start to get better. In the factory the find something unexpected, the blue girl in a scanner! They soon find out that this girl, is the older sister of Aelita, and she knows more things than the warriors.