After a bank robbery, four criminals escape to Mexico, but a storm causes an accident which takes down the plane where several die in the crash. The criminals take it into their own hands to continue when one survivor is attacked and eaten by a crocodile. The criminals kill it, but from then on the mother Crocodile is on a killing spree with a goal to kill each survivor. But that is not the only worry, because they’re trapped within it’s world, and if it doesn’t kill them, the criminals will.

The Caldwells take a family trip to Puerto Rico where their father is also securing a secret business deal, while the kids find their own paths. Eight years have passed since the events of Au Pair, and newly graduated as his high school’s valedictorian, Alexander Caldwell joins his visiting sister, college freshman Katie and her roommate Ariana on a family summer vacation with father Oliver and stepmother Jenny. Oliver and Jenny’s current nanny declines to join them and the over-worked parents/executives must take care of their newborn baby Sarah in Puerto Rico. Amidst corporate scheming by the young company CFO Walter Hausen, who is planning a takeover of Oliver’s company CCI Tekhausen (formed in Au Pair II), Oliver and Jenny must contend with bridging the generation gap with the family, new career motivations and the romances of their ‘newly reformed’ prankster kids.

New area deputy Jack Gales arrives on the island to find that a girl at the local Catholic girls school has been found dead. After investigating, he finds that students have been disappearing regularly for five years, about the time Mother Bernadette passed away. Gales and the Mother Superior’s secretary Cristina work together to try and unravel the mystery.