Idaho ski instructor Karin (Greta Garbo) marries vacationing New York City magazine editor Larry (Melvyn Douglas), convincing him to leave his hectic life behind. When Larry decides to return to the Big Apple for a few days, however, she refuses to accompany him. But Larry doesn't return when expected, so Karin secretly travels to New York City, where she catches him flirting with an old flame. Jealous, she intervenes, posing as her twin sister, Katherine, in an attempt to keep him faithful.