starstarstarstar-outline(3 stars)

“After the Wedding,” a gender-flipped remake of an Oscar-nominated 2006 Danish film by Susanne Bier, is, on one level, a showcase for Julianne Moore. As the actress demonstrated in the recent “Gloria Bell” — also a remake of a lauded foreign film , and, as with “Wedding,” one that boasts a producing credit by its star — Moore knows how to pick great material and make it her own.

Here, she puts even more of a stamp on it, since the story’s dynamics change in ways both subtle and significant as a result of the casting. These new — and, arguably, more powerful — dynamics are generated by not one actress here, but two: Michelle Williams, taking up the lead role originated by Mads Mikkelsen, and Moore, who steps into the shoes of Rolf Lassgard.

It’s impossible to say exactly how and why the new film works so differently from the original without spoilers. Suffice it to say that biology plays just as big a role as psychology, in a story that delivers one huge twist. That makes this “Wedding” not just more poignant but, in a way, also more problematic: By making male characters female — and vice versa, in the case of Billy Crudup’s Oscar, the husband to Moore’s character — the story creates new dramatic possibilities and new problems.

Adapted by writer-director Bart Freundlich, Moore’s husband, who has previously worked with her in “The Myth of Fingerprints,” “World Traveler” and “Trust the Man,” the story centers on Williams’s Isabel, an American do-gooder who has been working in an Indian orphanage for many years, and who must now make a reluctant pilgrimage to New York City to deliver a sales pitch to a wealthy business executive named Theresa (Moore) who is considering donating millions of dollars to Isabel’s cause. During the course of that visit — which coincides with the wedding of Theresa’s daughter (Abby Quinn) — Isabel discovers an unexpected connection with Oscar, a successful sculptor.

You may see that twist coming as it approaches, like a storm. Not because Freundlich mishandles it, but because it’s so substantial: more so, in fact, than in the 2006 film, simply by reason of what men and women are (or are not) capable of.

This sets up a mesmerizing double master class in acting — by Moore, to be sure, but also by Williams, who has the more challenging of the two roles, despite a second, somewhat melodramatic plot kink involving Theresa. One of the best actresses of her generation, Williams is never less than magnetic, in a role that calls up questions about Isabel’s motivation that would be hard, if not impossible, for many actresses to address believably.

Much of the film takes place just before, during and after the wedding day, as Isabel, along with us, is suddenly forced to digest new information about a history she shares with Oscar. For her, the storm metaphor is apt; it uproots everything, challenging Isabel to come to terms with something she thought she had buried long ago.

It’s hard, not just for Isabel, but also, at times, for the audience, some of whom may find it difficult to accept what happened all those years ago, despite the film’s scenes rehashing it.

But, true to its title, “After the Wedding” isn’t about something that happened way back when. Rather, it asks: What happens next? It’s in that space of the unknown that these two performers do some of the best work you’ll see this year.

PG-13. At area theaters. Contains mature thematic material and some strong language. 112 minutes.