Patrick Stewart narrates a landmark three-part series on the world s last mountain gorillas. Titus the gorilla king faces the biggest challenge of his life. He s lived longer and sired more offspring than any other known gorilla, but his time as a great leader may be coming to an end. The mighty silverback has a little orphan in his care - and both their lives hang in the balance. In Uganda, young silverback Marembo is back with his raging hormones and desire to be dominant - he s sure to shake things up a bit.