Polly and Ray are on honeymoon at Niagara Falls where they meet George and Rose, whose own marriage is falling apart. Polly later discovers that the brazen and alluring Rose has a lover waiting in the shadows and they are scheming to kill the emotionally unstable George - but Polly is unable to convince anyone of the danger as the murder plot edges toward a tragic conclusion. Thriller, with Marilyn Monroe, Joseph Cotten and Jean Peters.

Rose Loomis and her older, gloomier husband, George, are vacationing at a cabin in Niagara Falls, N.Y. The couple befriend Polly and Ray Cutler, who are honeymooning in the area. Polly begins to suspect that something is amiss between Rose and George, and her suspicions grow when she sees Rose in the arms of another man. While Ray initially thinks Polly is overreacting, things between George and Rose soon take a shockingly dark turn.