Five years after giving up his powers and separating from his friends, Leo San Juan has started a new life trying to focus on his family and their bakery, staying away from danger and adventures. However, Leo knows that his plans are rarely fulfilled and this time is no exception: while traveling with Nando to Veracruz, things start to get weird, and from the depths of the Tuxtlas jungle, an ancient curse has returned and only Leo can face it.
Ana, a nine year old girl, arrives with her mother to an isolated beach with the intention to rest and to know the sea. There, she discovers that they are under a terrible threat, therefore she is obligated to look for help with her father in order to save her mother.
A family lives in a cabin in the middle of a submerged forest in the mist and shrouded in perpetual twilight after an undefined global catastrophe. The father keeps his children locked in the basement into believing that a wild beast roams outside.
The story is about Katy, now grown up as a lovely butterfly, and her children, young twin caterpillars names Kiki and Koko, facing off against aliens who came to their forest searching for food which happens to be inhabitants of the forest. With the help of their friends, Katy, Kiki and Koko were able to defeat the alien X and save their forest and its inhabitants. The sequel to "Katy the Caterpillar."