Troll Hunter (15)

Starring: Otto Jespersen, Glenn Erland Tosterud

If you go down to the woods today – in Norway, that is – you're sure of a big surprise.

This elaborate mockumentary has a trio of student film-makers pursuing a story about bear-hunting and unearthing more than they bargained for. The mysterious woodsman (Otto Jesperson) in the Land Rover they've been tracking across country is no poacher. He is the last exponent of a noble yet secretive profession – hunting the giant trolls that inhabit the mountains and fjords. The writer-director Andre Ovredal has a droll time sending up Blair Witch-style DIY investigation, with characters conducting straight-faced discussions of troll lore: better not be a Christian if you go hunting a troll, or he'll smell you a mile off. When a new recruit to the docu-team says she's a Muslim, they ask the troll hunter if that's safe: "I honestly don't know," he replies. The film begins strongly, but once past the half-hour mark loses energy and direction. It also leaves an obvious question begging: having caught a troll on camera, wouldn't these tyro filmmakers simply hand it over to the TV news, thus instantly making their fortune and fame?