When a babysitting client says, "You're my favorite babysitter ever", Sam and Cat debate which one of them he meant. They compete for their new clients' affection to see who really is the best babysitter.
Sam, Dice and Goomer go to an MMA fight and leave Cat home to study. Upon returning, they discover that Sam's motorcycle is missing and Cat can't remember the day. The group sets out to solve the mystery and get Sam's bike back.
Sam and Cat's babysitting skills are tested when they look after a young boy, Oscar, who is very prone to accidents. The girls are determined to showing Oscar a fun time while struggling to keep him out of harm's way.
Cat's friend Jade comes to L.A. and Sam became friends with her. Cat invites Sam's old friend (and ex-boyfriend) to L.A. and things turn out so weird. Meanwhile, Dice gets a lot of tuna and it goes weird too.
Sam & Cat must find a way to enjoy their favorite drink after it's been banned from California. But once they manage to have as much of it as possible and share it with everyone else, they find the authorities are searching for the seller.