It's early fall when Ricky and Ellie travel to Portland from their homes in the Cascade Mountains for a weekend school exchange. Much to their surprise, they find an astounding variety of wildlife in the city. With the help of their new friends, Jenny and Marcus, they explore Portland's habitats, from its streets and gardens to woodlands, streams, and river banks. Ellie tests her bird-watching skills while Ricky learns ways to count fish in streams...