A high-concept romantic comedy is a difficult thing to pull off. The success of any romcom is so dependent on any number of ordinary yet intangible factors — star chemistry, warmth, a general sense of goodwill toward all involved — that when you massively complicate the rules of the game, the balance is thrown off. With “One Night Only,” those intangibles are largely in place: In Monica Barbaro and Callum Turner, it’s got two attractive, pleasingly grown-up leads whom you wouldn’t mind seeing get together; it’s set in New York City at its most invitingly balmy; it even has the odd one-liner that nets an actual laugh. (Not to be taken for granted in a genre increasingly heavy on dialogue with the cadence of jokes, but not the punchlines.)
It’s also saddled with a high concept so high as to neutralize all those considerable pluses, for once it’s introduced, not for a moment can you think about anything else. And it’s introduced mere seconds in, with a series of explanatory title cards sure to instantly bewilder any uninformed viewers who went in only wanting a perky date-night diversion. Three years ago, we are told, premarital sex was outlawed in the U.S. (What year the film calls the present is never established, though the world looks more or less the same as it does now.) For one night a year, however, the mandate is suspended, and the horny unwed are legally permitted to get it on. “It’s a lot,” conclude the title cards — and it sure is. Before anyone has even met cute, “One Night Only” sunnily swerves from “When Harry Met Sally…” terrain to thoughts of “The Handmaid’s Tale” by way of “The Purge.” Viewers may need some time to process.
