I just don't know how to feel about Channing Tatum anymore, but it's my weird job to figure it out. Since his breakthrough in 2006's "Step Up," Tatum has been so easy to mock, thanks to a parade of one-dimensional roles that didn't call for very much in the way of either nuance or shirts. Yet I can't help but notice that in his last few times out, Tatum seems to have gotten... well, if not better, at least less bad. (Though let's be honest: that was really the only available option.) He can be rather charismatic when he's not trying to emote, and he looks as though he was chiseled out of a block of marble, save for those adorably flawed bottom teeth jockeying for the lead in his mouth. Tatum isn't unpleasant to watch, but neither is he quite there yet, as evidenced by his uneven work in "The Vow."

You can probably tell from both the calendar and the generically romantic title that "The Vow" is this year's sappy Valentine's Day gift from Hollywood. Tatum plays Leo, who begins waxing philosophical in voiceover about how life is about "moments of impact," both literal and figurative. It's the former that we witness first in an unnecessarily detailed shot, as a truck rear-ends Leo's car and sends his wife Paige (Rachel McAdams) through the windshield. And while Leo waits for Paige to come out of her coma, he flashes back to their meet-cute at a Chicago DMV, to their sweetly sexy courtship, to their guerrilla wedding at the Art Institute, and to their married contentment as bohemian artists. Unfortunately, once Paige finally regains consciousness, she doesn't remember any of it, including Leo, her banged-up brain having essentially erased all memory of the last five years.

"The Vow" is not a Nicholas Sparks adaptation, but it may as well be, following his MO of throwing strange, sudsy obstacles in the paths of his would-be lovers. So even though "The Vow" is actually inspired by a true story, there isn't anything much odder than a husband having to re-woo his own wife, especially one whose last memory is that of being engaged to someone else. Paige's amnesia also blocked out all recollection of a rift with her icy, moneyed parents (Sam Neill and Jessica Lange), who are itching for a second chance to get their sculptor daughter back under their roof and on her abandoned law-school path. Leo, meanwhile, flits around purposefully as he tries to help his wife piece together remembrances of her current life, like her daily routines, her creative passions, and her eternally doting husband.

The five individuals (!) with a script credit on "The Vow" should be commended for not falling back on the ol' re-bonk to jog the memory, but all praise ends there. The characters are undeveloped stock clichés (Leo's hipster inner circle is hilariously awful, looking like anonymous extras in a Volkswagen commercial), and the dialogue consists mostly of helpful exposition and corny romantic platitudes. And though Chicago sparkles especially brightly, the supporting performances, including the usually underrated Scott Speedman ("Barney's Version") as Paige's slightly slimy yuppie ex, do not. But don't dismiss the ill-used Lange, who stops clutching her pearls long enough to deliver a wrenching third-act monologue on commitment. Lange's 11th-hour save adds a little weight to the film's alleged Big Revelation, which is, quite honestly, neither of those things.

As for Tatum, I'm afraid he's here to stay; besides "Haywire" and "The Vow," the man has THREE MORE FILMS scheduled to hit theaters before July 4. Tatum's reliably adequate here; with his puppy-dog eyes and quivering pillow lips, he's exactly what pop culture thinks women want. (See 2010's swoony "Dear John" for additional evidence.) More importantly, he enjoys playfully charged chemistry with McAdams, and this singlehandedly redeems "The Vow." McAdams, incidentally, rocks; she's essentially playing two characters here - quirky, charming pre-accident Paige and uptight, blueberry-mojito-drinking, James-Patterson-loving post-accident Paige - and her frustration at not being able to reconcile the two is both palpable and heartbreaking. Even surrounded by those unsubtle supporting turns, Tatum and McAdams are able to keep their business surprisingly dignified; in short, not the melodramatic tear factory you may have been afraid of or hoping for.