So much of the drama we respond to, from the heart, depicts ordinary flawed women and men navigating serious adversity or breaking through a wall of grief. And they are improved; their lives, their futures, are more connected and whole than before.

These stories are extremely difficult to write, and act, and direct, and sell to a summer crowd more interested in something with either zebras or lasers. For one thing, there's a vaguely icky pitfall: When things aren't quite right with the tone or the scale of the story, you end up with "Extremely Loud & Incredibly Close," which inadvertently processed the events of Sept. 11, 2001, as a coy self-improvement exercise for a preteen survivor.

"Seeking a Friend for the End of the World,"written and directed by first-time feature filmmaker Lorene Scafaria, struggles with similar implications, in a tale set in our planet's final weeks (an asteroid's about to hit). If the characters played, gamely and well, by Steve Carell and Keira Knightley find each other in such a scenario, surely that's a reasonable trade-off. True love. Total extinction. Right?

Scafaria's intention, I think, was different: to pose to the audience the simplest of all questions. What would you do in such a dire situation, with 21 days left on the clock? Set sort of in the present but a little bit in the future, "Seeking a Friend" finds insurance salesman Dodge (Carell) going through his paces even after the asteroid's imminent arrival has been confirmed. He works the phones in his increasingly desolate office building, offering the "Armageddon package" to policyholders. His wife, played in a brief bit by Carell's real-life spouse, Nancy Carell, takes the end-of-the-world opportunity to leave Dodge cold.

In the final weeks, the world goes crazy. Some kill themselves, or turn their social lives into a desperate last-chance orgy. (Rob Corddry and Connie Britton play Dodge's best friends, ready to par-tay.) Dodge at first settles, in his numbed state, for sliding into oblivion right along with Earth. Then he finds a note from his high school sweetheart, the one who got away, and sets into motion a plan to find her again. Dodge also meets neighbor Penny (Knightley), homesick for her parents back in England and stuck in a flat-lining relationship. Time for a change.

Thus begins the road trip for Dodge and Penny. The highlight, for us, at least, is a stop at a T.G.I. Friday's-like chain restaurant called Friendsy's, where the hugs never stop and Scafaria's sense of humor flowers into a satisfying set piece. Scafaria wrote the script for the droll romantic odyssey (nonapocalyptic division) "Nick & Norah's Infinite Playlist," and she's clever; she knows how to spin variations on a theme of longing. Her debut directorial assignment has all sorts of polish and assurance.

What it doesn't have is a way of making sense of its comic and dramatic strains, together, in the same movie. Carell and Knightley work hard to bring life and truth to each stage of a dawning friendship. By the end, though, Dodge and Penny have had one too many affirming encounters that feel engineered, not lived.

mjphillips@tribune.com