Carmen and Juni think their parents are boring. Little do they know that in their day, Gregorio and Ingrid Cortez were the top secret agents from their respective countries. They gave up that life to raise their children. Now, the disappearances of several of their old colleagues forces the Cortez' return from retirement. What they didn't count on was Carmen and Juni joining the "family business."

Carmen's caught in a virtual reality game designed by the Kids' new nemesis, the Toymaker. It's up to Juni to save his sister, and ultimately the world.

Eight years after the third film, the OSS has become the world's top spy agency, while the Spy Kids department has since become defunct. Retired spy Marissa is called back into action, and to bond with her new stepchildren Rebecca and Cecil, she invites them along to stop the evil Timekeeper from taking over the world.

Exploring the further adventures of Carmen and Juni Cortez, who have now joined the family spy business as Level 2 OSS agents. Their new mission is to save the world from a mad scientist living on a volcanic island populated by an imaginative menagerie of creatures. On this bizarre island, none of the Cortez's gadgets work and they must rely on their wits--and each other--to survive and save the day.