At the onset of the Japanese invasion of the Philippines in 1942, American private pilot Chip Corbett is using his personal plane to fly out fleeing individuals for a price. One such client, a shady war profiteer, is the last client to leave the mainland on Chip's airplane under a hail of bullets from the invading Japanese. However, the airplane develops technical problems and crash-lands on the island of Corregidor where a few Americans and Philippine guerrillas still hold-out. Recognizing Chip's client as one of the most infamous Philippine traitors who collaborated with the Japanese in exchange for money, the Philippine guerrillas kill the man. Chip is left unharmed, since he's American, but the defenders of Corregidor seem disgusted that Chip can only think of money instead of helping with the war effort. Chip finds out the Philippine guerrillas are attempting to salvage the national gold reserves from the clutches of the invading Japanese. The plan is to transfer the gold bullion onto a barge and eventually on board an American submarine waiting off shore. However, the approaching submarine is destroyed by a Japanese dive-bomber and the gold is left on the barge. Japanese warships are seen patrolling the coast line. The only solution seems to be the sinking of the barge and the gold stashed on top of it. The Philippine guerrillas plan to recover the sunken gold after the war when Japan would be defeated. But the barge is too big. They need to find a way to bomb it from above in order to sink it in relatively shallow water. Chip suggests he could fly a small airplane loaded with bombs and destroy the barge from the air. He asks if there is a plane laying around. American nurse and missionary, Joan Barnes, who is providing medical assistance to the guerrillas, explains that her missionary father, Dr. Barnes, does missionary work among the native head-hunter tribes inland. Her father owns a small sea-plane that could do the job but the way to him is fraught with dangers. Nevertheless, a small group is formed, led by a Philippine guerrilla colonel and guided by Joan who knows the way through the jungle. Chip volunteers to be the pilot of the sea-plane, provided he is rewarded for his efforts by allowing him to keep the sea-plane and fly it back to the USA after the barge is sunk. In the morning, the small group heads toward its destination, facing difficult terrain, areas infested with Japanese soldiers, native head-hunters and other perils.