Arthur and Mike

A divorced, deadbeat dad, played by Colin Firth, fakes his own death and hooks up with Emily Blunt's Manic Pixie Dream Girl for an all-American road trip. Woo-hoo! Arthur and Mike ought to be an absolute riot.

Except it isn’t. Not even a little.

Firth's character, Wallace – a desperate, depressed void of a man – leaves behind a lover (Anne Heche), an ex-wife and a teenage son who can't stand him. A former golfer, Wallace hopes to steal the identity of another golfer, Arthur Newman, so that he might take up a post on a course in Indiana.

Identity theft becomes something of a grim habit: en route to the Hoosier state, Wallace meets hot mess Charlotte (Blunt), a schizophrenic klepto who has assumed her twin sister Michaela’s identity, and now calls herself Mike.

Wallace/Arthur and Mike/Charlotte begin an affair, and find solace in breaking into empty houses and taking on the absent owners’ identities. Will this unorthodox romance survive? Or will they both wise up and return to face their responsibilities?

Unhappily, even stars as charming as Firth and Blunt can't raise viewers' dampened spirits. US highways have seldom seemed as unappealing: the sun glowers mercilessly, rather than shines, from North Carolina to Indiana. Becky Johnson, who previously wrote the screenplays for Under the Cherry Moon and Seven Years in Tibet, codes deep ideas about acting and impersonation. However, like the road trip and the offbeat romance, it's hard to see where this is going. Or why we'd ever want to visit.

It's a mystery how Firth and Blunt became attached to such an implausible story populated by such unbelievable people. Might this be is a low point for careers that have already been varied enough to take in to Salmon Fishing in the Yemen and Gambit?