This is the first book in a two book set that comprise one very long story, broken into two books in order to keep the size of each book to a reasonable size.  The second book of the set, immediately following this one, is Stydle the Strong.

Summary.  Gideon and his gang, ranging up to about 15 members, have come down from Watertown and are causing trouble on the river bank.  They steal pets from area residents, kill the animals, and have them stuffed.  They also steal other things, including every boat they can get their hands on.  They destroy a snowman with a bomb, threaten the boys with guns, try to burn down the clubhouse, try to bomb the clubhouse, destroy a Pelham shack, chop down a tree with a treehouse in it, and severely beat several Club members and Pelham members.  The book ends with Gideon being very sick and out of the action, and his even nastier second-in-command Stydle taking charge of the gang.