Eight years have passed since the events of the third film and the OSS has become the world's top spy agency. Meanwhile the Spy Kids Division has since become defunct. Retired spy Marissa Wilson is chasing her arch enemy Tick Tock despite being nine months pregnant. After giving birth she and her family find that time seems to be speeding up, and later find that Tick Tock is actually a henchman of a man named the Timekeeper, who has unleashed a plan called "Project Armageddon" to get people to spend more time with their families instead of on mindless pursuits. Marissa takes her two stepdaughters Rebecca and Cecil to the OSS where they meet up with her cousin Carmen Cortez and estranged brother Juni Cortez where they must team up to stop the Timekeeper and show the relevance of the Spy Kids Division.