When 12 year old Moose Flanagan finds a note in one of his freshly laundered pillowcases, he knows exactly who it's from: Al Capone. Capone may be one of the most notorious criminals in residence at Alcatraz, but he and Moose have a special connection. And now, it seems, Al Capone wants Moose to do something for him. As Moose and his friends work together to figure out how they are going to help one of America's most notorious gangsters, some other inhabitants of Alcatraz are trying to get away with something of their own...