Besides her room and her grandparents’ backyard, Libby has one other place that she considers her very own: under the Willow Tree in the park. The tree’s long limbs hide a park bench and the little “nature houses” that Libby has built next to the truck. As far as she knows, this place is known only by herself and her mother — but one day she spots a little pug dog coming out from below the branches. Who could that dog be?