Duncan (Liam James) is 14 and feeling a strain on his relationship with mum Toni Collette, caused by her overbearing new boyfriend, Steve Carell. While he dreads going away with them for the summer, things start to look up for Duncan when he befriends the scruffily likeable manager of the local water park, played by the scruffily likeable Sam Rockwell.

Unfortunately for anyone looking to fill a Descendants-shaped void, this is a far breezier affair that, while undeniably entertaining, doesn’t pack the emotional uppercut of Alexander Payne’s film. Perhaps that’s because Payne didn’t direct this, but writers Nat Foxon and Community‘s Jim Rash themselves, turning up as Roddy (water-park perv) and Lewis (water-park weirdo) respectively. This means schmaltzy moments underlined with the strum of acoustic guitars and a misjudged bit of cartoonish humour involving three kids and a water-slide.

On the plus side, there are big laughs to be had, particularly where Allison Janney’s outrageous Betty is concerned (though a running gag about her lazy-eyed son gets old fast), and Duncan’s increasing disappointment with his mum is expertly handled.

However, after a brilliant opening scene in which Carell ruthlessly orders Duncan to rate himself out of 10 as a person (allegedly inspired by a similar conversation Rash once had with his own stepfather), boyfriend Trent deflates into a standard “boo-hiss” baddie instead of being explored as a human being. AnnaSophia Robb, so good in Bridge to Terabithia, is equally left hanging without much material as love interest Susanna. No-one plays fragile mums like Toni Collette though, so all’s good there.

The major problem, unfortunately, is Liam James as our everyman hero of the story. While he plays Duncan with the right level of awkwardness (especially when he takes things too literally), he doesn’t bring the requisite heft to the more dramatic moments. As such, these come off stilted and clunky when they should be heart-breaking or thrilling.

Of course, none of this matters too much in the end. While it misses a couple of tricks, The Way, Way Back is as warm and sunny as the summer we kind of had for a bit a few weeks ago. It was fun while it lasted, but it didn’t leave a mark.

Released in UK cinemas on Wednesday 28 August 2013.