In the midst of the war of 1812, a British frigate fires upon a peaceful, unwitting mercantile ship. In the attack, the trader's captain (Robert Barrat) is killed and the British take the surviving crew prisoner, including sailor Dan Marvin (Victor Mature) and the late captain's willful daughter Corunna Dorman (Louise Platt). In captivity, Marvin and Corunna form an uneasy alliance and, along with the other prisoners, plot an escape. Their goal: Reclaim their ship and avenge the murder of their captain.