▁has ▁to ▁put ▁up ▁with ▁his ▁alco hol ic , ▁g amb ling ▁father ▁Brian ▁( Fran k ▁Morgan ). ▁Just ▁before ▁his ▁first ▁major ▁fight , ▁Tommy ▁lear ns ▁that ▁his ▁oppon ent ▁has ▁been ▁injured ▁and ▁has ▁been ▁replaced ▁at ▁the ▁last ▁minute ▁by ▁Tommy ' s ▁good ▁friend , ▁former ▁world ▁champion ▁Johnny ▁( Will iam ▁G arg an ), ▁trying ▁to ▁make ▁a ▁com eb ack . ▁During ▁the ▁bout , ▁Tommy ▁k ills ▁Johnny ▁and ▁is ▁named ▁" K iller ▁Mc Co y " ▁in ▁the ▁newsp apers . ▁He ▁then ▁comes ▁under ▁the ▁control ▁of ▁powerful ▁book maker ▁Jim ▁C ain ▁( Ed ward ▁Arnold ). ▁ ▁While ▁training , ▁Tommy ▁meets ▁and ▁falls ▁in ▁love ▁with ▁C ain ' s ▁daughter ▁She ila ▁( Ma ure en ▁O ' S ull ivan ). ▁C ain ▁has ▁been ▁very ▁careful ▁to ▁keep ▁his ▁daughter ▁from ▁learning ▁about ▁his ▁profession . ▁C ain ▁tries ▁to ▁break ▁up ▁their ▁rom ance , ▁but ▁without ▁success . ▁ ▁Tommy ▁wins ▁fight ▁after ▁fight , ▁becoming ▁a ▁cont ender . ▁If ▁he ▁wins ▁his ▁next ▁bout , ▁he ▁will ▁get ▁a ▁shot ▁at ▁the ▁world ▁championship ▁title . ▁However , ▁" P ug " ▁Wal sh ▁( N at ▁P end leton ), ▁a ▁tra itor ous ▁associate ▁of ▁C ain ' s , ▁has ▁both ▁She ila ▁and ▁Brian ▁kid n apped . ▁He ▁orders ▁Tommy ▁to ▁lose ▁the ▁fight ▁in ▁the ▁e ighth ▁round , ▁or ▁else . ▁Tommy