The Healing Sand (Book Three: The Hole Stories)

Onus and Twig have ruined another of William Ernest Fang's elaborate plans and are finally on their way home. But a chance encounter with a very broken man leads the boys to a strange town hiding two big secrets: one, the town possesses a magical healing sand, and two, the sand, which is used for so much good, has a dark side to it...a dark side that may keep the boys from ever getting home.