The Cortez family is off to Spain for a family reunion with Nana. But just as they arrive, the OSS Agency pages them with another mission. A crazed Spanish architect is constructing buildings all over Madrid with a chemical that makes everyone extra sleepy. He's bent on creating a sinister siesta! Carmen and Juni will have to stop the evil plot or else say adios to more than just the Spanish capital!

When their parents go on a spy mission to Brazil, Carmen and Juni are assigned two babysitters from the OSS. But when one sprouts tentacles and the other whiskers, they realize that these are spies on the prowl--and Carmen and Juni are on their own to solve the case.

The OSS has discovered that an evil family plans to take over the world, using a new hit reality show. With the world to save and a competition to win, the Spy Kids take on this evil family, both on the screen and off.