Ulises and Lía sign up for Total Adventure, an extracurricular activity offered by the school which, as its name promises, takes them on a total adventure!   In Ulises and Lía's school, students can choose between various extracurriculars. Against their will, both end up in Total Adventure class with Professor Hache, a strange, gruff old man. What Ulises and Lía don't know is that the professor is hiding a secret and they are about to embark on a thrilling adventure. Ulises and Lía realize that they must return to Eternia to help its inhabitants. When they arrive, to their horror they discover that the Eternians have contracted a virus that is weakening them. With the help of Roxlo and Professor Hache, Ulises and Lía set out to find the solution. But it won't be easy.