Hank Smith, a brutish stoker on board a freighter, is appalled when Mildred Douglas, a society girl forced by circumstance to travel as a passenger, visits the stokehold and recoils at the filthy, sweating Hank. A powerhouse of a man with a primitive confidence, Hank has never been looked down on before nor suffered the insult "hairy ape" flung at him by the rich girl. At first he seeks vengeance for the insult, but broods over it until more than anything, he desires to understand it. When the ship reaches port, he seeks her out in her upper class surroundings, determined to grasp the meaning of the encounter.