The Doctor takes Ace back to her hometown of Perivale, only to find that something is very, very wrong. Many of Ace's old friends and neighbors have disappeared while domestic pets become victims of unseen kiillers. Will the hunter become the hunted when only the fittest survive? A race of galactic hunters called the Cheetah People have found a way to transport themselves to Earth-- and the entire human race is their prey.… (more)