In this narrative, the Doctor and his companions investigate the mysterious disappearance of a Concorde aircraft at Heathrow, discovering that it has been snatched into a prehistoric time warp. Upon traveling 140 million years into the past, the crew encounters Kalid, a malevolent magician who uses psychic Plasmatons and illusions to enslave the missing passengers. The Doctor eventually unmasks Kalid as his arch-nemesis, the Master, who is attempting to siphon energy from a gestalt alien intelligence known as the Xeraphin. Through the bravery of the Concorde pilots and the Doctor’s technical ingenuity, the Master is outmaneuvered and exiled to a distant planet. The story concludes with the safe return of the aircraft to the twentieth century, though Tegan is inadvertently left behind at the airport as the TARDIS departs.