The Doctor and Jo Grant land in the middle of a prison break, only to find that the Master has hypnotised many people. After their trances are broken, the Brigadier informs the Doctor that they all work for the Freedom Corporation, which had been set up thirty years ago. The Doctor decides to investigate the Freedom Corporation. He attends a demonstration given by Gerald Gooder to show off his time machine. The Doctor is relieved to find that Gooder doesn't know what he's doing, but is still suspicious. Late at night Jo and he sneak in to the building. They find Gooder destroying their prototype time machine. They follow Gooder to find the Master, who traps the Doctor in the construct. The Doctor and Jo are trapped, with no way out.