The story takes place aboard a transatlantic ocean liner. A passenger named Brisbane is puzzled when the steward behaves oddly while taking his luggage to his stateroom, number 105. In the middle of the first night, Brisbane is further perplexed when his roommate suddenly leaps down from the upper berth and runs out of the cabin. In the morning, Brisbane learns that his roommate has gone overboard - and was the fourth consecutive occupant of the same upper berth to do so.