Ruth (Jeanne Crain) and John (Carl Betz) board a ship for their honeymoon. However, within 15 minutes of sailing, John has disappeared. Not only has he disappeared but there has never been any trace of him and there are no witnesses that have seen the couple together. The room that they originally booked into is now empty and only Ruth's suitcases seem to be located on board - in a different room! So begins the mystery. The film follows Ruth's attempts to locate her husband while we are introduced to a suspicious cast of characters. No-one believes her story and even the confidante that she finds in Dr Paul Manning (Michael Rennie) has his doubts. She receives a phone call in her cabin from John saying that they are both in danger.......

The film gets you involved from the beginning and you know that something sinister is occurring. The various characters are introduced to us - eg, stewardess Anna (Mary Anderson), single traveller Kay (Marjorie Hoshelle), steward Jim (Casey Adams) and a foreign passenger with a walking stick (Karl Ludwig Lindt) - and we are never quite sure what is in the back of their minds. Even Dr manning is not above suspicion. The fog horn that continually sounds adds to the tension in the night scenes and it is a well acted film by all.