In "Four to Doomsday," Peter Davison's recently regenerated Fifth Doctor is burdened by the most irritating trio of companions in the history of the show (Adric, Nyssa, and Tegan) when the Tardis materializes inside a vast starship with a multiracial crew from Earth's distant past. Downloaded into computer chips are the memories of the 3 billion survivors of the Urbankan race, and the Earth is to be their new home. Meanwhile, Monarch, a giant green frog-thing, wants to travel back to the Big Bang to meet God, who he is convinced is himself.