The Frontiersmen (1938) William Boyd starring as Hopalong Cassidy

The local school is causing Hoppy problems. First Bar 20 cattle are stolen when Hoppy investigates a problem there. Then the new teacher arrives and disrupts the routine of the Bar 20 hands. Later with the Bar 20 hands at graduation, the rustlers are poised to strike again. But there is dissension among them, and this will lead to the break that Hoppy needs.