Summer in February

It's incredibly bad form to judge a movie by its poster but on some occasions it can tell you everything you need to know. Piranha 3DD doesn't look like a Tolstoy adaptation and it doesn't pretend to be. Which is fine. Summer In February looks like woolly-jumper-on-a-heath movie, a niche subgenre indigenous to English cinema and Sunday afternoon TV, which is where this limp drama would feel more at home. The poster is bang on.

Aspiring artist Florence Carter-Wood (Browning, Sucker Punch) arrives in Cornwall on the eve of World War One hoping to study among other budding artists and writers that have converged on a sleepy estate of Lamorna, which has doubled up as a colony, a kind of proto 60's bohemian hangout. She immediately makes eyes at dashing Boer War veteran Captain Gilbert Evans (Stevens) and the feeling is more than mutual. Then, however, she makes off with Dominic Cooper's poem-quoting, beer-swigging Lothario, creating a destructive love triangle in the process.

Dan Stevens plays it safe in his first foray into film after bringing the dashing gent of Downton Abbey to the public's attention – his Gilbert is just another Matthew Crawley; same clothes, same hair, same stiff upper lip, same stilted emotions, same dialogue. We can't blame him, though – would we really accept him as a cigar-chomping wise-cracking action hero? Someday maybe but for now if it ain't broke, etc. Browning is saddled with a morose character who's not allowed to smile or be happy so it's left to Cooper, the only one with a bit of life about him, to have fun amidst all the seriousness.

Although based on a true story Summer In February doesn't make with the believability. The plot is bullied into situations to create drama: There is no reason why Browning and Stevens can't be together – they love each other and even her father (Nicholas Farrell) is on board with the match – and the love triangle feels so artificial so the entire movie is just overly complicated foreplay.

It looks nice, with its cosy cottages and wind-swept cliffs, but Summer In February just isn't good. And it's a bad title.