The film is set in a not-too-distant future where premarital sex is outlawed, save for one night a year. And go crazy they do, with almost every shot in the movie showing people hooking up, in at least the background. I shudder to think what this movie would have looked like if it took the X-rated approach, though that movie would have at least been memorable. It’s all corny, in traditional rom-com fashion, but mildly engaging, especially when compared to what else the movie has to offer. The bad news about “One Night Only” is pretty much everything else about the movie.