Molly and Dave head to Issaquah, Wash., to transform the Brandt's backyard into a habitat for the band-tailed pigeon and the illusive mountain beaver. They'll take an existing pond and make it into a clean water source, build a platform birdfeeder and cover a birdhouse with moss to help it blend into the surroundings, making the band-tailed pigeon feel more comfortable. Along the way they'll head to a local cougar park to show this mountain family how to live peacefully with the area's cougar population. When it's all said and done, the Brandt's yard will be certified by the National Wildlife Federation.