Aliens from Outer Space are slowly switching places with real humans -- one of the first being a young man about to get married. Slowly, his new wife realizes something is wrong, and her suspicions are confirmed when her husband's odd behaviour begins to show up in other townspeople.
When a local man's corpse appears on a nearby hillside, no one is quite sure what happened to him. Many of the town's residents secretly wonder if they are responsible, including the man's ex-wife, Jennifer, and Capt. Albert Wiles, a retired seaman who was hunting in the woods where the body was found. As the no-nonsense sheriff gets involved and local artist Sam Marlowe offers his help, the community slowly unravels the mystery.
In late 1941, with no hope of relief or re-supply, a small band of United States Marines tries to keep the Japanese Navy from capturing their island base.
