Dr. Dan Proctor is in love with his sickly patient, Evelyn Heath, and brings her to his idyllic home in Maine, where she is welcomed by his picture perfect family for a recuperative summer stay. In her efforts to steal away Dan's married brother Douglas, Evelyn proceeds to wreak havoc on every member of the household with her neuroses and manipulative behavior. Her victory seems assured, until Aunt Martha appears, determined to put an end to Evelyn's schemes.

An accomplished cast highlights this film-noir production directed by John Brahm. Ann Baxter's role foreshadows her classic, Oscar-nominated performance as Eve Harrington in All About Eve (1950). Ralph Bellamy was one of Hollywood's most popular, versatile, and long-lived actors. In 1958, he won a Tony Award as Best Actor for his dramatic role as Franklin Delano Roosevelt in Sunrise at Campobello. Ruth Warrick was a member of Orson Welles' Mercury Theatre troupe and is best remembered for her role in the classic Citizen Kane (1941). Margaret Hamilton's face is instantly recognizable as the Wicked Witch of the West in The Wizard of Oz (1939). Guest In The House earned an Oscar nomination for Original Score.

Baxter once again proves to be a wolf in sheep's clothing as a manipulative young woman who moves in with the family of her betrothed (Bellamy, for once not the jilted suitor) who also happens to be her psychiatrist. She gradually turns the house full of happy, loving people against each other, and they are powerless to stop her. Academy Award Nominations: Best Scoring of a Dramatic or Comedy Picture.