Island of the Fendahl

The Fendahl is the death of evolution, the horror that lies in wait at the far end of the food chain.

The Fendahl is death itself.

And the Fendahl is dead. The Doctor destroyed it many years ago, in another incarnation, when he encountered it in a place called Fetchborough.

But if the Fendahl is dead... how can it live again, on the remote island of Fandor?