Walter (a mouse) and Xavier (a duck) are best friends who do everything, including sitting in comfortable silence, together. “Until … quietly … slowly … they weren’t.” Over several page turns, the illustrations show the arrival of Penelope, a hedgehog, who really hits it off with Xavier. Penelope and Xavier are shown chatting as they walk side by side, while Walter trails behind despondently; and although they try to include Walter, “it wasn’t the same.” “Walter’s world quietly … slowly … changed.” Feelings of grief and loss, sadness, and loneliness, consume him for a while. He even feels as though he hates Penelope and Xavier, though that’s not really true. He simply misses his friend. But of course, on one particularly sunny day, things don’t feel quite as bad, and Walter decided to go out for a hike by himself, taking a new trail and enjoying the outdoors. When he encounters someone new, a badger named Ollie, it makes it all the better. A quiet, emotionally realistic story of changing friendships acknowledges feelings of loss and offers gentle encouragement. (Ages 4-7)