While Sophie Mouse and her forest friends are playing in the snow one day, they accidentally wake a hibernating hedgehog named Pippa, who is a little grumpy at first, but Sophie, Hattie, and Owen show her all the fun things to do in wintertime.

Sophie Mouse wants to prove how wonderful mice are for a school project she is doing with her brother, Winston, but starts to have doubts when, even with Hattie and Owen's help, she is unable to learn to swim.

Sophie Mouse's little brother goes missing in the fourth book of The Adventures of Sophie Mouse. Sophie's brother Winston really wants to help Sophie and her friends build a fort at Butterfly Brook. But Sophie doesn't want her six-year-old brother hanging around, and she tells him he's too little to join. Soon after Winston leaves, Sophie realizes that they could use his help after all. So she returns to tell Winston he's welcome to come along-but...