The Phantom Light

Sam Higgins alights at the Welsh village train station to take over the North Stack lighthouse. He meets Alice Bright, who begs to accompany him as part of a 'psychic society' investigating the phantom lighthouse. He refuses to take her along.

Sam reports to Harbour Master David Owen. Owen reveals that Sam's predecessor vanished, and the chief lighthouse keeper before him disappeared as well. He mentions a major shipwreck a year ago blamed on the phantom light, setting the stage for peril around the lighthouse.

Jim Pearce attempts to bribe Sam to take him to the lighthouse, but Sam sees through the ploy and suspects Jim is not a mere admirer or reporter. The exchange hints at hidden motives and possible espionage at the lighthouse.

Alice overhears Jim asking about hiring a boat to reach the lighthouse and makes another attempt to charm him, but fails again. Her persistence underscores her willingness to participate in the investigation, as well as the murkiness of Jim's motives.

Owen, Dr. Carey and others transport Sam by boat toward the lighthouse. Dr. Carey examines Tom Evans, a mentally disturbed resident of the station. Evans tries to strangle the doctor, who concludes Tom cannot be moved in his present state, so Sam ties him up to keep him contained.

Sam introduces his remaining assistants, Claff Owen and Bob Peters, as part of the guard at the lighthouse. They join the others in maintaining order and monitoring the crew and equipment during the tense voyage.

Jim arrives on a boat that runs out of petrol, bringing along his stowaway Alice. The unexpected passenger raises questions about their true goals and loyalty to the mission.

Sam begins interrogating his uninvited guests. Alice explains she is an actress hiding from the police after a knife fight between two admirers, adding another layer to her cover.

A fire breaks out near Tom's bed, heightening the danger and suspicion around the staff. The incident increases the tension as everyone contends with the escalating crisis.

Sam overhears Jim plotting with Alice and learns Jim is not a reporter after all. He fears saboteurs may be at work, intensifying the peril around the lighthouse.

Jim has Alice hang a radio aerial from the bunk-room window, but Tom, whom Claff has untied, sees the act and slips away to observe. The moment hints at the danger of transmission and the players' hidden moves.

Jim tells Sam he is a naval officer planning wreckers to sink the Mary Fern for insurance; Alice then reveals she is a detective from Scotland Yard. The confessions complicate loyalties and deepen the mystery surrounding the crew.

Jim begins transmitting a warning to the approaching Mary Fern, but Bob and Claff are knocked unconscious, the light is sabotaged, and a decoy light is turned on. The plan appears poised to mislead the ship and trigger disaster.

After Jim sends Alice to fetch Sam, Tom knocks Jim out and disables his radio. He then locks Alice and Sam in with him, wresting temporary control of the situation from the saboteurs.

Jim climbs down the lighthouse to alert the coast guard, while Claff unlocks the door and Sam proceeds to repair the light. They overhear Dr. Carey talking to Tom, revealing the doctor as the mastermind. The Mary Fern is saved just in time, but the doctor, cornered at the top, chooses to jump.