Keepers who raised orphan elephants return to the wild to find them, a surrogate mother to an orphaned chimp returns to his sanctuary to see how she is received, and a scientist who has spent his life working with black bears attempts to prove that a bond can be developed between bears and their cubs and humans.

What's it like to be best friends with a wolf? Or a penguin? In this episode we meet people who have formed special bonds with rhinos, lions, wild deer and a pangolin - one of the most endangered animals on the planet – and see how these bonds endure as human and animal are reunited in the wild.