Captain Holling is relieved of command due to a nervous breakdown, replaced by Captain Downey, who takes over just as the ship is about to be used for an experiment in remote control. Professor Grimson's system allows him to control the ship from land, but a rival group is listening in, hoping to use the device for their own purposes. After the professor is fatally attacked, Major Pope investigates and decides to join the trip, unaware that at least two passengers are enemy agents.
Mystery Liner
As investigators on a lavish cruise, they must navigate a sea of deceit and treachery to solve a murder that has shaken the ship.
