When private tutor Thomas Arnold (Sir Cedric Hardwicke) becomes headmaster at Rugby, a boy's preparatory school in England, he puts into place a policy of strict punishment for unruliness and bulying. Arnold finds an ally in Tom Brown (Jimmy Lydon), a new student who is subjected to hazing and abuse by a group of older boys and is pressured by his friends to keep quiet about it. Fed up, he leads his fellow classmates in an underground rebellion against their tormentors. But certain unspoken rules still apply at the school and Brown loses his hero status when he is accussed of breaking the Rugby code of silence.