Adolescence is a rough time for everyone experiencing it. For 14-year-old Duncan (Liam James), this tumultuous growing period is compounded by having to spend summer on unfamiliar ground with a pseudo-family. Trapped in a vacation cabin in the Cape Cod area, Duncan is forced in close quarters with his divorced mother Pam (Toni Collette), her overbearing boyfriend Trent (Steve Carell), and his daughter. An opening scene featuring a back-handed lecture from Trent immediately informs us that Duncan has no desire to be a part of this family, and we don’t blame him.
Duncan is a typical moody teenager that doesn’t even attempt to make the best of a bad situation. He wears jeans to the beach, he never wipes the sourpuss off his face, and he has no discernible sense of humor. Mad at his mother for dating the oppressive Trent, Duncan does whatever he can to get as far away from them as possible. In this case, it means trading in the salty water at the real beach for the chlorine-scented artificial Water Wizz water park.
While moping around poolside, Duncan is noticed by Owen (Sam Rockwell), the park manager. Owen is outgoing, fun-loving, and his dialogue is an endless stream of jokes. Naturally, Duncan gravitates toward Owen, who is the perfect fit to be a summertime sage. Duncan also attracts the attention of Susanna (AnnaSophia Robb), the slightly older girl next door. She has her own family-related issues, spending the season with her divorced mother Betty (Allison Janney), who hides her pain with alcohol and high-energy.
