After a police raid, commanding officer Alberto has confiscated a large sum of money from a powerful drug dealer named Bartolomé. Bartolomé is pure evil and wants his money back, so he makes a plan to recover his money that involves kidnapping Alberto's son and forcing Alberto's wife, a famous runner, to run the local marathon.

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."