Magnum, P.I. (1980): Season 4, Episode 8

4 - 8: A Sense of Debt

After he runs into - literally - Vietnam veteran and professional boxer Leon Platt, T.C. steps into the ring in order to win a boxing prize that will save the man and his daughter from destitution. Higgins summons Magnum back from a job in Detroit to help before T.C.'s sense of guilt knocks him out for good.