The Adventures of Peter Wheat #53

Peter Wheat hears from Blue Jay about a band of wild mice roaming a valley across the lake and sets out on his mouse mount to investigate. After discovering the white mice herd with their magnificent leader, Peter decides to pursue the white mouse mount for himself, riding his current mount into water and underwater passages to follow them. Peter and his mouse mount are captured by the wild mice band and taken to a tree castle, where Peter realizes that his desire to catch the white mouse has distracted him from the fact that the Wheat Folk have been driven into the hills by a wizard and his knights who may now be in possession of the magical kingdom.