It is late in the summer of 1954 in the Catskill Mountain town of Delhi, NY. John Hoffman, Buzzy Fancher and the other members of the River Rat Gang are about to enter ninth grade at Delaware Academy. As a last summer adventure they explore the old Delaware Academy school building nd get more than they bargain for. Autumn finds the River Rats plotting to disrupt the high school Halloween party. Winter brings tobogganing and exploring an abandoned barn; spring, an encounter with the tough uptown Trucker gang in the old powdered milk factory.