The Doctor and Sarah Jane are stranded on planet Exxilon, whose ancient civilization has fallen into savagery.

The Doctor has promised Jo a holiday on Metebelis 3, but the TARDIS materializes not on the famous blue planet, but in the cargo hold of the SS Bernice, sailing to India in 1926. Despite all appearances, the Doctor insists that they are no longer on Earth, but Jo's not convinced, at least not until a sea dinosaur attacks the ship! Millions of miles from Earth.