Bear Island, known as the wartime graveyard of the Arctic, where Nazi submarines lay in wait for the Murmansk convoys, is the setting for Alistair MacLean's novel. As the charter ship Morning Rose sails through wintry seas towards the island, the doctor on board, Christopher Marlowe, is kept busy attending to his sea-sick patients - the members of a film unit who are to make a film on Bear island so secret that none of them know much about it. Then another, more mysterious malady attacks them and in some cases proves fatal. But there us something highly unnatural about both the illness and its selection of victims. The Morning Rose has a murderer on board. Marlowe realizes that he is included in the elimination campaign. Before the ship has anchored under the towering cliffs of Bear Island, there has already been an attempt on his life. Then, in the encampment, events on board fuse into a pattern of terror as suspicion shifts from one member of the company to another, and further deaths take place. Someone in the film unit is intent on preventing Marlowe and others from sharing the secret of the island, and what lies beyond the Gates of Pearl. Beset by the conflicting temperaments and nationalities within the frightened group, Marlowe contends with grim humour against weather, terrain and ruthless adversaries, as events build up to a tremendous climax in the darkness of the Polar night.