 Against his personal preference, PT boat commander Ward Stewart is made executive officer of the submarine USS Corsair. On leave before sailing, he meets schoolteacher Jean Hewlett and gives her a romantic rush...unaware that she s the sweetheart of Dewey Connors, his new commander. At sea, the men bond while fighting German Q-ships. When will they discover their mutual romantic rivalry? Will it interfere with a spectacular commando raid on a secret German base?