The painfully true story of welterweight boxing champion Barney Ross is detailed in Monkey on My Back. Cameron Mitchell stars as Ross, whose meteoric ring career is interrupted when he joins the Marines at the outset of WWII. A highly decorated hero, Ross contracts malaria oversees and is given morphine to assuage the pain. By the time he returns to the states, Ross is a confirmed drug addict. Before he can rise to the top again, he must hit rock bottom and his descent into the hell of narcotics dependency is graphically illustrated (so much so that the film was almost denied a Production Code seal). Though a cured Barney Ross served as technical advisor for Monkey on My Back, he ended up suing the producers for defamation of character -- and lost.

Après sa première défaite, Barney Ross, un champion de boxe, va peu à peu sombrer dans l'amertume. Celui-ci décide alors de s'engager dans les Marines où il se distingue, durant la guerre du Pacifique. Mais à son retour il est traumatisé par la guerre et devient, cette fois-ci, dépendant de la Morphine...

Durante la Seconda Guerra Mondiale, l'ex campione del mondo dei pesi leggeri Barney si arruola come marine a Guadalcanal. Contratta la malaria sul campo di battaglia, torna in patria come eroe nazionale ma è costretto a ricorrere a dosi massicce di morfina per resistere alle fitte di dolore. Cadrà nell'abisso della tossicodipendenza.

Barney Ross, "el orgullo del gueto", alcanza la fama al alzarse como campeón mundial de boxeo sin haber sido vencido en el ring. Durante la guerra, en Guadalcanal, se convierte en un héroe, y así regresa a su país; sin embargo, también trae consigo una fuerte adicción a la morfina que le obligará a combatir en la peor de las guerras.