Square Shoulders.

Tad's dream is to attend a military academy so he can grow up to be a great soldier and a war hero, like his father. What he doesn't know is that his father, Slag, is actually a thief and a derelict. Slag robs a factory in order to get the money to send Tad to military school, then gets a job at the academy's horse stables to be close to his son, who doesn't know he's alive.