There’s nothing like the end of the world for bringing people together, if your timing is right. (Otherwise it’s a bit of a drag.) The basic conceit here, if you can buy into it, is that the giant asteroid Matilda is due to crash into and destroy the planet Earth in three weeks. This “liberates” some people to no end, licensing them to go bonkers with drugs, sex, partying, running out on bad relationships, overeating … It’s a screenwriter’s wet dream, meaning that anything goes in terms of plot and story. Why, it could even wrap itself around a romance or even a romantic comedy.

Conceived as a vehicle for Steve Carell, Seeking a Friend for the End of the World seems to be designed to slide his comic persona toward leading man status–a romantic lead, yet. However, things can, and do, go awry.

Chief and foremost, his co-star–the brilliant Keira Knightley–steals the movie. If the rest of the movie were as good as Knightley’s acting, we’d have a charming, first-rate film on our hands. The first part is broad comedy, dime-store satire. Making hay out doomed people’s slapstickian behavior, it may be diverting to a casual audience but not, I think, to Carell or Knightley fanz. As written and directed by Lorene Scafaria (Nick and Norah’s Infinite Playlist, a charming trifle), SAFFTEOTW immediately lurches when our insurance agent character (Carell) watches his wife literally run away from their marriage just as soon as news of the asteroid is broadcast.

Carell becomes a sad sack confessing his secret fear: dying alone. As luck, and plot devices, would have it, he meets up with his neighbor (Knightley), who’s been “stealing” his mail. She’s just broken up with her boyfriend. Hmm… Two lonely, scared people at loose ends in the face of planetary destruction. What d’ya think?

Once the two team up because they have people they want to see–his old girlfriend and her mom and dad–the film switches to a Road Movie. As the duo make for the proper locations, there’s an entertaining cameo featuring William Peterson (CSI) as a doomed truck driver. They visit one of Knightley’s old boyfriends, who lends them a new vehicle. None of this is bad, mind you–it’s mildly diverting. But then the comedy starts thinning out to make room for evolving romantic feeling between the middle-aged man and his new young friend.

So, what happens, do ya think? Does the world really end? Do the two fall in swoony love? How? Why?

Knightley, along with Emily Blunt, is one of our best young actresses, able to handle a diversity of roles. Though Knightley walks away with the film, it suffers from mood swings and tonal inconsistencies which no actress could overcome. Carell has not yet found his mass-audience persona, and seems tamped down. He seems, after the film’s first l5 minutes, rather bland, underplaying much too much.

The problem with Scafaria’s movie is that she has far more ambition than talent; you can see what she’s aiming for–the end-of-the-world plot hook is a terrific if not fully realized gimmick–but she does not quite make it. She’s a promising writer-director but not yet seasoned. This movie needs to be funnier and Carell better directed.

In sum, the movie is okay. It’s just not the end of the world.