Two years ago Mrs. Phillips, the housekeeper, gave William a very special token which enabled him to shrink down to the size that could fit in the small castle in the attic. Now, two years later, William is facing a different kind of challenge. His friend, Jason, has fulfilled the requirements of the local coming of age tradition by "jumping the freight" trains. William doesn't want to equal this feat and in the nick of time, Mrs. Phillips sends him the token once again and this time the two boys enter the castle in search of adventure, both shrunk down small enough to fit in. William receives a hero's welcome but soon the boys find themselves in danger. There is a rat determined to lead his rat army against the human beings and he intends to destroy them all. Can William find the courage in himself to meet this mighty foe when he did not have the "right stuff" to jump the freight? 224 pages Ages 9-13