A supertanker heads north in heavy weather on Thanksgiving Day. When the Captain orders reduced speed, the new Chief Engineer refuses to comply, saying he can't run the big diesel any slower or the engine will be damaged. Old Spenser, the ancient mariner aboard the ship knows that both officers have a crush on the pretty female steward. He has seen many dangerous voyages during his years at sea and knows the vessel is in danger. A timid man who fears bullies, he has always resisted taking sides. Now, he must and he does. The consequences of his actions surprise even him.