Capt. Roger Kimbro leads the starship Archipelago and it's crew on a mission to a distant planet. They are there to plant a device on the planet but before they can complete the mission, they're attacked. The planet was supposed to be uninhabited but they awaken in a chamber made by the Ebonites, aliens they once fought in a war. One by one, they are questioned and tortured. The package they were to deliver is a super weapon, a doomsday device to be exploded on an uninhabited planet to show their enemies what they now had. When one of them gets access to the device, she activates it but learns too late where she is.