A young merchant marine officer's faith in his authoritarian captain is shaken when mysterious deaths occur, leading him to suspect that Captain Stone's mental unbalance endangers the lives of the ship's crew. The crew, believing the vessel is haunted and cursed, refuses to support the officer's concerns, but a cryptic radiogram and an illiterate crewman's internal monologues spark doubt among the crew members. As tensions escalate, Captain Stone's grip on reality falters, culminating in a tragic confrontation that ultimately exposes his madness and leads to his downfall.