Some of the world's most endangered species are at risk when a potentially fatal disease makes it on to the estate. Keepers in the giraffe house are on tenterhooks as they wait to see if a newborn calf survives the critical first few days. And it looks a bit like a bear and a bit like a cat but smells of popcorn - will an exotic new arrival be the key to a breeding programme that could save a species?

A specialist wildlife cameraman from the BBC's Planet Earth series arrives at the park to film Longleat's most impressive feeders. His subject is a chameleon who has a tongue which flies out four times faster than a jet fighter. But what if it doesn't want breakfast?

Meanwhile, Kate Humble and Ben Fogle discover the lengths keepers go to for the animal orphans, while Jean Johansson sets up a tug of war for the lion pride. Elsewhere, the stakes couldn't be higher as vital testing for a killer disease continues. But when tragedy strikes, can the keepers recover from the unthinkable?