"I wanna meet someone different. With half a brain." "Around here?" That's what Kieran tells best friend Sam in Julian Kerridge's tale of teenage drama. Growing up in a dead-end beach town, Sam wants to do something with his life, while Kieran is happy to drink all day, ignore his girlfriend Moony, and visit Pirate Land, the naff local theme park.

Then in walks Lori and changes everything. Clever, kooky and philosophical, she's not the Albanian pikey that Kieran thinks, and Sam is blown away. It's a typical Manic Pixie Dream Girl scenario, as Lori introduces Sam to art galleries, spontaneous running through parks and other such quirky activities, and Seamonsters perfectly captures the fantastical world of new romance with nicely-lensed landscapes and heady music.

But Kerridge's co-written script has more brains than that, pulling down that mythical stereotype and exposing the ongoing conflicts underneath. It's a good move, which allows the cast room to breathe, but it also leaves the story with an awkward final act that doesn't know which relationship to focus on. Fortunately, the four main actors are uniformly superb, nailing the angst and importance of small everyday events and keeping you engaged as alliances switch within the group - watch out for each in years to come.

The likeable tale loses momentum as the teens move to London and a few supporting characters (the camp cafe owner, the old woman trying out online dating) are under-developed, but despite the slight flaws, Seamonsters has a real sense of the atmosphere of growing up. "I feel like I was watching a film in the cinema and someone came in right in the middle and stopped it," laments Sam after the first hour has finished. A smart kid, that one.