Release Message:  The Doctor (Tom Baker), Sarah and Harry teleport to Earth to ensure the planet is safe for the survivors on-board Nerva Beacon

Description:  The Doctor, Sarah and Harry teleport to Earth to ensure the planet is safe for the survivors on-board Nerva Beacon to return to Earth and re-inhabit their world. Only to find a Sontaran named Styre has captured a group of humans and conducting experiments on them to discover the human body's weaknesses, as part of the Sontaran's goal for domination of the galaxy.