Year One (12A)

In the beginning was the nerd, and the nerd was good – actually the nerd is the best thing in the knockabout Primitive Man comedy Year One.

Michael Cera is the sweet-faced kid who edged nervously into the movie consciousness as Ellen Page's put-upon boyfriend in Juno and was thereafter co-opted by Judd Apatow's gang of clowns. Here he plays Oh, a shy, self-deprecating member of a tribe of hunter-gatherers. He's about as useless a gatherer as his friend Zed is as a hunter, the latter played by Jack Black in his self-aggrandising, pretend-cool style. Neither of them is much cop when it comes to romance. When Oh confesses his infatuation with a tribe girl, Zed recommends he hit her on the head with his club – "Women respond to that."

The film, promisingly, is directed by Harold (Groundhog Day) Ramis, who cites the great Mel Brooks skit "The 2000-Year-Old Man" as his inspiration. The gimmick is to overlay the dangers of ancient life with the knowingness of modern comedy. Zed and Oh live in huts of wattle and dung, but yearn for a life beyond hirsute machismo. Zed reckons that the fruit from the Forbidden Tree of Knowledge might be the key. "What if eating the fruit makes me the wisest man in the village?" he asks. "That's a pretty low bar," replies Oh. After yielding to temptation, both are banished from the village and forced to make their way in the outside world.

Here's where Year One withers and dies. Ramis has got his comic premise, but instead of constructing a plot, he and his co-writers work up only some feeble vignettes. Zed and Oh stumble through a mock-biblical landscape, where they happen on Cain murdering Abel, manage to stop Abraham sacrificing Isaac, fall into the clutches of Roman slavers and fetch up in Sodom, where a hairy-chested Oliver Platt is the high-camp high priest. It's always disheartening to sit through a comedy and realise that the best gags are the ones you've seen in the trailer. When Abraham (Hank Azaria) suggests that the menfolk surrender their foreskins to the knife, Oh worriedly offers a counter-suggestion: "Couldn't we just pierce our ears or something?" So there's an occasional laugh, but most of the time the gags – indeed, whole scenes – just peter out. Early on, we watch Oh yell in fright as a cougar leaps on him from a branch; then Ramis cuts to the next day. Even accepting it's a spoof, you're still inclined to ask – how did he escape that cougar? Cera remains quite endearing, though there's not much comic rapport between him and Black, who's coasting – along with the screenwriters. I'm not sure they will have an audience keenly looking out for Year Two.