There is great activity in the Hollister household upon the arrival of Domingo, the donkey promised Sue in New Mexico. The excitement mounts higher with the discovery of a note attached to the donkey's halter signed Y.I.F. So begins one of the two mysteries that run through this book. In the midst of the approaching Christmas season, the Hollisters work out a plan to use Domingo in a special project to provide gifts for the poor children of the town...