(The Doctor checks the console.) DOCTOR: 116 parsecs...must be the planet of Ribos. DOCTOR: A hole...? Even the ones on the console. GUARDIAN: The Key to Time is a perfect cube, which maintains the equilibrium of time itself. The Doctor and Romana step out. These segments must be traced and returned to me before it is too late, before the Universe is plunged into eternal chaos. You know of the Key to Time?
Plan: A: the Doctor; Q: Who is given a difficult task by the Guardian of Time? A: the six segments; Q: How many segments of the Key to Time are there? A: the Universe; Q: Who must be saved from eternal chaos? A: Romana; Q: Who is the Doctor's new assistant? A: the planet Ribos; Q: Where does the Doctor and Romana travel to on their mission? A: the first segment; Q: What segment of the Key to Time is protected by Shrivenzale? A: the monstrous Shrivenzale; Q: Who is protecting the first segment of the Key to Time? Summary: The Guardian of Time gives the Doctor a difficult task,and a new assistant. Together they must search for the six segments of the Key to Time, to prevent the Universe from being plunged into eternal chaos. On their mission, the Doctor and Romana travel to the planet Ribos where the first segment of the key is protected by the monstrous Shrivenzale.