Welcome to Big Sky Mountain: a home for everyone! Rosa has come from the city to live with Grandma Nan in the wilds of Big Sky Mountain. And what surprises are in store for her! Grandma Nan is not exactly an ordinary grandma, and Big Sky Mountain is like nowhere Rosa has dreamed about before. Grandma Nan lives in an old wooden cabin with Albert the moose and Little Pig the pygmy owl, and spends every day out on adventures.