A female astronaut, Sam Walker, returns to Earth after her first spaceflight, but the capsule's entry into the atmosphere goes awry. For a short while, contact with the spacecraft is lost, the capsule sustains damage, and Sam's body is found to be covered with bruises and cuts, and as a result the descent module crash-lands in the middle of the ocean. Sam is rescued and placed in quarantine in a luxurious and secluded forest mansion in Virginia under the supervision of General William Harris, her adoptive father. Sam notices that her wounds are not healing, and unexplained events are happening in the house. Sam begins to suspect that something extraterrestrial has returned with her from space.