After an atomic explosion blasts the Moon out of Earth orbit, Moonbase Alpha drifts in space, with 300 people on board. When a rescue team from Earth arrives in a faster-than-light space ship, everyone is overjoyed that they can now return to Earth. But Moonbase Commander John Koenig, having undergone an experimental brain soothing process after receiving a concussion in a crash on the Lunar surface, sees not friends from Earth but gruesome monsters which have telepathically caused all others on...