On an ocean liner crossing from New York to Europe in 1947, a passenger says her name is Mrs. Lindsay Grant, and her new husband Kenneth has disappeared after boarding along with her. What's worse, her key now doesn't fit their double room, but a nearby single room where she finds her luggage, but tagged with her maiden name Thompson. The ship's records show that room booked by Lindsay Thompson, the double room vacant. Lindsay says the maid saw her with Kenneth; the maid says not. Lindsay has no marriage license or ticket; she says Kenneth had them. Radio inquiries reveal that Lindsay had a breakdown after being accused of killing her first husband: could this husband be a figment of her imagination? Only two people, the doctor and a friend Lindsay made during the trip, seem to think she might be telling the truth.