It's 2040, and a group of astronauts have been sent on a dangerous mission to retrieve water from Europa, one of the several moons orbiting the planet Jupiter. After narrowly escaping the moon to head back home, the team discovers that a nuclear war has left earth uninhabitable. While the remaining male astronauts come to grips over their losses, one of the crew members spontaneously transforms into a woman (in a scene that is as shocking as 1979's Alien). Each character tries to uncover the mystery of this horrific event. Was it an act of God, or a biological reaction for keeping the human race alive? As the men vie for the last female in existence, they begin to turn on one another. All of the questions come to a head in a shocking finale.