Duncan (Liam James) is an awkward 14-year-old kid trapped in the back seat of of a station wagon driven by Trent (Steve Carrell), the guy dating Duncan's mother, Pam (Toni Collette).
Trent's taking Pam and Duncan, along with his own daughter Steph (Zoe Levin), to his beach house for the summer, a trip Duncan desperately wants to avoid, preferring to spend the summer months with his estranged father.
But, with his father apparently unable to look after him, Duncan is forced to hang around the beach house, taking orders from Trent and stick from Steph.
Salvation seems likely to come in the form of the neighbours, the hilarious, if not alcoholic Betty (Janney) and her kids, Pete (a slightly younger, but far less awkward geek with a lazy eye) and Susanna (AnnaSophia Robb), the quirky love interest who takes a liking to the quiet Duncan.
And while they offer hope, and Betty becomes a close friend of the socially awkward Pam, it's the random encounters with Owen (Rockwell), the owner of a local waterpartk, that is the heart of the story.
The presence of Carrell - in a surprisingly dialled back performance - and most notably the marketing campaign imply that The Way, Way Back is a knockabout comedy. But it's so much more than that.
Although peppered with unpleasant characters, this isn't a movie about justice or comeuppance (although you might wish it was at times), it's about the characters you like learning from their surroundings, while those you don't stand still.
And thanks to Rockwell and newcomer James, it's a journey that's utterly compelling and completely believable, partly thanks to the use of real locations (you too could visit Water Wizz next time you're in Massachusetts).
That's not to say it isn't laugh out loud funny. The investment in the characters makes the comedy all the more hilarious when it does come, not least the asides that come courtesy of every trip to Owen's water park where his motley crew of water park attendants offer the family atmosphere sorely lacking in Duncan's home life.
The dialogue sparkles, delivered by a cast on top of their game, in a movie that aims for subtlety rather than bravado. Writer/ directors Jim Rash and Nat Faxon's directorial debut is a sweet, knowing tribute to teenage awkwardness, to divorced parents trying to restore family values and to those who find themselves as unlikely mentors.