Continuing their quest in search of the Keys to Time. The Doctor, Romana and K-9 travel to the cold planet "Calufrax" in search of the second segment to the Key to Time. But the TARDIS accidentally lands on the planet Zanak, which is ruled by the robotic space pirate The Captain. Only to discover Zanak can travel across the galaxy and nobody on Zanak, isn't who they appear to be.