1/4 The Doctor and Romana head to Calufrax but find that another planet has taken its place.
4/4 The Doctor and Romana are pursued by the Graff and attacked by the ferocious Shrivenzale.
3/4 The Doctor and Romana's search for the first segment is hampered by the Graff Vynda-K.
2/4 On Ribos, a lump of jethrik is really the first segment of the Key to Time.
1/4 On a mission to assemble the Key to Time, the Doctor and Romana travel to Ribos.