Kate Humble and Ben Fogle return to Longleat Safari Park for another spectacular summer series following the fascinating stories of the exotic animals and the keepers who look after them.Today, the team are braced for the arrival of a species that hasn't lived at the park for 30 years. Longleat is already home to a collection of eleven wallabies, but the park's visitors often confuse them with kangaroos, which are much larger. The best way to teach them the difference is for the two species to live side by side, so a kangaroo is making the 400-mile journey from Edinburgh Zoo to join the collection in Wiltshire. But keeper Gemma is worried. She has looked after wallabies for years and knows they can be quite tricky to control, but kangaroos can grow to more than double the size and are capable of jumping eight metres. Just how big is the animal that she will have to look after?Elsewhere, another new arrival is causing a stir. The native Eurasian beaver has returned to the estate for the first time in 400 years. This isn't just good news for the park but also for the environment. Beavers are nature's ultimate engineers, and their dam building encourages other species to take up residence. In an astonishing development, the Beaver Trust has been called in because some footage exists that might prove that the beavers have had babies.Zoologist Megan McCubbin feeds the only Californian sea lions in the world who share their home with hippos, and she finds out if, after a traumatic summer, the wolves will unite for a morning howl. Meanwhile, wildlife cameraman Hamza Yassin may have met his match when he is set a photography challenge by Animal Park legend Ian Turner.