John Brickley (Robert Montgomery) believes in PT boats, and as a lowly U.S. Navy lieutenant stationed in the Philippines, that makes him a radical thinker. "Your boats maneuver beautifully," an admiral (Charles Trowbridge) tells him, "but if I'm going into combat, I prefer something a little more substantial." The gently delivered but stinging dismissal stirs the resentment of Lt. "Rusty" Ryan (John Wayne), who tartly tells Brickley that he wants to be transferred to destroyers. The Pearl Harbor bombing makes transfer impossible, especially with the Japanese preparing to invade the islands. So Brickley and Ryan go to work, first as message carriers between the Philippines and Corregidor, then, finally, as ship hunters. They record some successes, but it's a doomed effort: The Americans are hopelessly outnumbered by the Japanese, and with almost all of the Pacific Fleet destroyed at Pearl Harbor, they know help won't arrive to save them. As the Japanese push the U.S. forces back, Brickley and Ryan and their crews hop from island to island, scrounging supplies and taking casualties but keeping up the fight. Just as it appears that they will be forced to fight on Corregidor against the Japanese, they get rescued; they're ordered home to promote their PT-boat successes, and they take the last plane out, hoping to return and avenge their defeats.