Code Lyoko follows the adventures of four "ordinary" students who discover the existence of a mysterious parallel universe, a virtual world called Lyoko. The students, Yumi, Ulrich, Odd and Jeremy discover that both Earth and Lyoko are being threatened with destruction by a super virus, X.A.N.A., which has infected the Super Computer that controls everything. Now the students, who are joined by Aelita, a virtual being from Lyoko, must lead double lives : ordinary boarding school students on Earth and action heroes inside the digital world of Lyoko, where they learn each have special powers.