Mercy Island (1941)

Warren Ramsey (Ray Middleton) is an ambitious young lawyer whose ultimate failure might be traced to his ruthlessness, insanity, or a blow on the head. Marooned on an island with his wife Leslie (Gloria Dickson), his friend Clay Foster (Donald Douglas), and the seaman Captain Love (Forrester Harvey) and the Guide (Bill Shirley) who had led them there. He finds an old man, Doctor Sanderson (Otto Kruger), who had fled there after a pitiful accident, who is unjustly under suspicion of murder. Ramsey's mental state causes him to imagine that Leslie and Clay Foster are having an affair and he has a plan to put an end to that. His decision, for his personal prestige, to bring the innocent Dr. Sanderson back to face trial is contested by the whole party, and finally prevented by fate, design,accident or possibly an angry alligator.