The new film, “Carol,” from director Todd Haynes, is beautifully acted, beautifully costumed and designed, and beautifully shot. Fans of “Mad Men” should definitely go see it – it’s got the same languid pacing and the same meticulous attention to the details of mid-century style and manners. But there’s something that bothered me at the heart of the film, and I’m wondering whether anybody else felt the same way.

“Carol” tells the story of a love affair between two women in the early 1950s: a younger, mousy woman, Therese (Rooney Mara), who aspires to be a photographer, and an older, glamorous woman, the titular Carol (Cate Blanchett), who is a suburban matron. Both women are already entangled with men – Therese is dating a fellow who badly wants to be her fiancé, while Carol is married (albeit in the process of divorcing), and has a young daughter. They spot each other across the crowded floor of the department store where Therese works, and there is an instant mutual fascination. Carol engages in some high-Hollywood flirting, and then leaves her gloves behind, presumably strategically. Therese contacts her to return them – and we’re off to the races.

Well, actually, there’s a bit of a dance before things get racy, as Carol, despite her obvious attraction for Therese and her transparent efforts to reel her in, is a bit hesitant at crossing the line that would constitute an outright pass at the younger woman. But they can’t stay away from each other. And when her soon-to-be-ex-husband, the on-the-nose-named Harge (Kyle Chandler), discovers her new infatuation, he flies into a rage and uses Carol’s behavior to wrest custody of their daughter from her. This is when Carol throws caution to the wind, and invites Therese on a cross-country road trip to forget her troubles, which Therese accepts over the furious protests of her uncomprehending beau.

Notwithstanding the amount of time that passes before the two women express their mutual passion physically, though, this is a story of love at first sight. Their mutual attraction is not based on mutual knowledge; it’s there the instant they meet. Nor is it particularly fed by anything they share after that moment. It’s striking, actually, how little they speak to one another, how little they reveal; even so famous a believer in chance and chemistry as Sky Masterson, when he actually figures out which doll is for him, does quite a bit of singing.

But that’s not really what bugs me about their romance. What bugs me is . . . I can’t figure out who Therese has fallen in love with.

Mara gives a fully integrated, deeply felt and wholly persuasive performance as Therese, a woman raised to please who hasn’t figured out what pleases her, and who doesn’t quite know what to do with the feeling of being so powerfully drawn to Carol. But Blanchett’s performance is highly mannered, almost draggy in the degree to which, when she is with Mara, she is performing the role of glamorous femme fatale.

I am quite certain this is a deliberate choice, whether Blanchett’s or Haynes’s, both because I have seen Blanchett do so much varied work on both screen and stage that I know what kind of range she’s capable of, and also because, when she is away from Mara, her performance becomes much less mannered, much more direct and genuine. When she’s fighting with her husband, or chatting with her old friend and former lover Abby (Sarah Paulson), or going things over with her lawyer, she seems like a person. When she’s with Mara, though, she puts on this femme fatale act.

Which – again – is totally fine. People do that to attract people they are attracted to. They perform; they create a persona. It’s not even necessarily conscious. There’s something interesting to be explored about the way in which Carol finds herself boldly seducing Therese, and then pulling back from what her actions mean, and then moving forward again. That’s what attraction is like.

But is that enough to carry the story?

“Carol,” based on a somewhat autobiographical Patricia Highsmith novel, ends happily – atypically, to say the least, for a 1950s story of same-sex romance. After abruptly dropping Therese so as to fight for custody of her daughter, Carol realizes that she can’t live this way (and that the custody battle will itself do irreparable harm to her and Harge’s child), and so she gives Harge the custody he wants and asks only for regular visitation, and for him to let her go, and be herself. And then she reaches out to Therese  who, after briefly contemplating life without Carol, accepts her offer of a life together.

My wife was nonplussed by the ending, because she compared Carol’s situation to that of Diane Keaton’s character in “The Good Mother.” If she could ditch Liam Neeson so as to protect her relationship with her daughter, then couldn’t Carol ditch Therese? But that’s precisely what Carol tries to do, and only later does she realize that it won’t work – both because her husband won’t be mollified that way and because there’s a difference between turning away from someone you love and turning away from yourself, from who you are. She’ll be no good to her daughter if she does that, she says – and I believe her.

But I still don’t know how to read that purportedly happy ending, because I don’t think Therese knows who Carol is. She’s fallen in love with an image – of glamour, of sophistication, of wealth. But she doesn’t really know her – and, frankly, she’s just starting to know herself, and become herself, in the months after Carol drops her. And then, at the first opportunity, she goes back to her. Is this really where she should be?

Of course, we don’t know how long the arrangement lasts. It could be a beautiful love affair that lasts a year. Carol could find Therese a comfort; Therese could learn a great deal from Carol. And then they could move on, perhaps remaining friends. But that’s hardly what we want to imagine happens after the credits run. We want to imagine something far more enduring has been forged. And, I’m sorry, but that’s not what I saw happening, and so when the credits rolled my first thought was, “is that all there is?”

It’s a feeling which, to my mind, hangs over too much of the film, and unfortunately makes it, well – a bit of a drag.