Charlize Theron stars as Mavis, a writer of factory-line young adult novels in the Sweet Valley High mode whose career is about to come to an end; her series is being discontinued, as no one much cares about teenage romance these days unless there are vampires involved.
Even without that blow, Mavis would be a bit of a mess; she's a serious drunk who's never really left adolescence. So when she discovers that her old high school sweetheart (Patrick Wilson) and his wife have just had a baby, that somehow triggers in her the conviction that he really does still love her, and she just needs to go remind him of that.
Once Mavis arrives in her old home town, she winds up spending much of her time with Matt (Patton Oswalt), another former classmate. They hadn't been close in high school, and they only meet now because they happen to be at the same bar.
The performances are good. Theron is to be commended for her absolute commitment to Mavis's loathsomeness; there's not an ounce of typical movie star "you must love me" in the performance. And over the last few years while no one was really paying attention, Oswalt has turned into quite a good actor, and he's the best thing about the movie; he's nursing his own high school wounds (literal and metaphoric) in ways that are only slightly more adult than Mavis, and he's perhaps the most immature voice of reason the movies have ever seen.
But Diablo Cody's script falls flat. You wouldn't expect from these characters the same sort of whiplash-inducing pop culture references that you got in Juno, but what we get in its place is a steady drip of nastiness and cruelty. Despite the best attempt of all involved, it's hard to make that either funny or entertaining. This is the first Reitman movie that's left me feeling sort of meh.