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.

This year, Santa’s daughter takes her first trip away from the North Pole during the Christmas season hoping to find adventure and love in sunny California. While Santa watches his daughter through a magic snow globe, Annie arrives in L.A. and becomes friends with the owner of Candy Cane Inn, Lucy, and her daughter, Mia. She also quickly lands a job at Wonderland Toys. Wonderland Toys’ owner, Ted is struggling to stay in business selling old-fashioned toys in a digital world. Annie soon realizes that she wants Ted’s business to thrive because she has feelings for this Christmas traditionalist.

While working underground to fix a water main, Brooklyn plumbers—and brothers—Mario and Luigi are transported down a mysterious pipe and wander into a magical new world. But when the brothers are separated, Mario embarks on an epic quest to find Luigi.