In 1944, the castaway Corporal Allison drifts in a raft to Tuasiva Island, where he meets Sister Angela. She tells him that she is the only person on the island, having been left behind when seeking out a priest. The nun and the marine are stranded, but the island offers a bountiful supply of food. However, their paradisiacal life ends when the Japanese arrive to build a base, forcing "Mr." Allison and the nun to hide in a cave. The marine's expertise in such conditions proves to be vital to their survival, and the two grow ever closer.