Travelling at Christmas, wealthy young Nicky Collins (Durbin) thinks she sees a murder from her train window but when she arrives in New York she can't get anyone to believe her. But not willing to give up, Nicky turns to Wayne Morgan (Bruce), a mystery writer for help. Recognizing the victim from a newspaper photo, Nicky checks out his family and gets mistaken for a nightclub singer (so Durbin can vamp a torch song). Lots of comedy amidst the mystery and romance, and some surprizes as well. Based on a story by Leslie Charteris.