Episode Title:Mystery of the Weird Looking Walrus.Episode Description:While deep-sea diving in the Bering Sea to solve a mystery of why walruses are so weird-looking with Aviva's newly rebuilt manta riders, the Kratt Brothers discover that Zach Varmitech has stolen a rare and priceless pearl. They soon learn that Zach plans to trade it to Donita Donata, in return for her partnership with him in his next evil plot, until Zach loses the pearl in the sea. The Kratts are then forced to search for the pearl while trying to save the walruses with walrus power to stop Zach who has captured them to be his robotic slaves to find the rare pearl.