An opaque tower of pink-ish flesh, rising actor Channing Tatum has the imposing heft of an action star — there's a little b-boy humor wrapped around all the meat and tissue that immediately suggests he'd be best with a handgun and a tough guy quip. And yet his first real big break was as a soulfully dancing street kid in Step Up, a decidedly soft high school fantasy. A few years and a handful of small movies later, he landed the action hero role he seems physically destined for, as the main lunkhead in the noisy, senseless G.I. Joe: The Rise of Cobra. (A sequel is coming this summer.) And yet he didn't quite seem to fit in there, did he? Amid all that unironic swaggering and chest-puffing, Tatum seemed like a boy playing dress up. Same for his Roman centurion picture The Eagle (actually not a bad way to spend a Saturday night, fyi), in which he affected a high school declamation-style Serious Voice as he stentorianally barked out words like "honor" and "father." No, he seemed more at home in Step Up, and in the Nicholas Sparks soldier romance weepy Dear John. Sure in these movies he's supposed to be a hard guy, but he's just the hardest thing in a vat of goop. Turns out Channing Tatum's a girl's guy, someone who personifies the vulnerable meathead, the secretly sensitive brawler, that is the object of so many adolescent girls' fantasies (and likely some adolescent boys', and some adults', too).

Which is why he seems perfect for a movie like The Vow, the new romance from director Michael Sucsy, written by a committee of five credited writers (and based-ish on a true story). Here Channing Tatum gets to be sad and in love, just like his fans want him, while his florally delicate costar Rachel McAdams both suffers and melts in his arms. Perfect. So what does he play? A cop? Another soldier? Some kind of underground krav maga prodigy? Well, um, actually, no. In the most glaring of the several ways this movie surprises you, he plays a Chicago hipster who owns a recording studio, an openly sensitive guy who marries his pretty young sculptor wife (also a hipster, or the movie's idea of such) at the Art Institute and loves nothing more than drinking wine out of mismatched glasses while sitting in mismatched chairs at the local boho cafe. The part itself isn't exactly beyond Tatum's scope — we're dealing with a range of Meat Is Happy to Meat Is Angry to Meat Is Sad — but the details of the character fit him as strangely as his Eagle armor. And he seems to know it, as he's willing to wear the bulky, drapey cable knit sweaters and even a jauntily crooked hat in one scene, but seems to draw the line at the tight jeans that are a requisite part of the modern urban artiste uniform. Nope, that is a bridge too far, and so he teeters (he walks like a penguin, doesn't he?) around in '90s-esque Brian Austin Green b-ball baggy jeans. The silly jeans serve as a signifier of how Tatum oddly stands out in his movies, how they always seem to be straining to include and define him and yet are unable to get a firm grasp on him. (But there's so much to grab!) He's better in The Vow than he is in, say, Fighting, but still he seems both bigger and smaller than the movie. It's not quite right.

That said, The Vow almost works on the whole, as a Valentine's Day tearkjerker about love's enduring persistence. At the start of the film, Tatum and McAdams are newlyweds leaving an art house movie theater on a snowy night. While driving home there's a bad accident and McAdams' character, Paige, suffers a traumatic brain injury. When she wakes up from her coma days later, everyone is relieved and grateful, of course, only to quickly realize there's one small problem: Paige can't remember anything from the last five years and thinks she's still in law school living a preppy Evanston life with her financier fiance, not shacking it up on the North Side with Hipster He-Man over here. And so the movie proceeds, with a few flashbacks to tell us this couple's origin story, while in the present Paige struggles to reconcile the life she thinks she's leading with the strange one that Tatum's Leo insists she's been living. The movie sets up the boundaries of the old and new lives a little too strictly — are we really to believe that someone just flips a switch one day and goes from cardigan to keffiyeh, from law school to art school, condo to loft, that completely? And while we're at it, do any of those things really define a person? There's a strange and silly emphasis on hair and wardrobe signifying character in this movie, perhaps a pander to the younger swooners in the audience who don't exactly understand the weird dynamics of old-life friends mixing with new-life friends (something the movie handles well) or anything else a little more adult. I like the concept of Paige remembering only the life she gave up and not the one she threw herself into, I just wish it had been done a little more thoughtfully and with an eye toward the blended, blurry middle-ground.

Aside from Tatum's wet woodenness, there's some perfectly decent acting in The Vow. Rachel McAdams is always like watching a particularly lovely sunset, with all her warm blush hues and glowing globe eyes. And she's wholly appealing in this; though her character is frustrating at times, you can't seem to stay mad at her. I do, though, wish she'd maybe get a new agent or manager or something, because someone of her talent and magnetism should be in far more respectable fare than this. Or Morning Glory, or The Lucky Ones, or The Time Traveler's Wife. Maybe she likes the sappy stuff, but there's a sharp spark in her in Mean Girls and a wisdom about her in the excellent Slings & Arrows that suggest she's capable of much, much more. Ah well.

As Paige's gently devious WASP mother (she wants Paige to never remember the old-new life and return to the old-old one), Jessica Lange (yes, really!) has one delicious scene of Lange Acting that prevents her from going to waste. That the Lady Lange is in this at all seems strange until you remember that Sucsy also directed her in the terrific HBO movie Grey Gardens. Like that far superior effort, this film has an air of aching melancholy about it, only here it's flatter and more basically stated. Still, The Vow is not entirely ineffectual, with enough occasions of deft and subtler-than-expected writing to hold up the heavier, dopier stuff.

There's also a cadre of embarrassingly costumed hipster friends and Scott Speedman, looking older and more angular but no worse for the wear, as the crisp former fiance, and they all provide this at times surprisingly thorough movie with perhaps unnecessary but in no way unappreciated details and nuances. The Vow is not, may I remind you, a Nicholas Sparks movie. There are more smart things in play in this movie than there are in the entire Sparksian filmic oeuvre combined, though that's not saying all that much. But yes, you could do a lot worse for a cozy V-Day date flick. It's perfectly satisfying, if not unforgettable (har har).