Monk Costigan, having managed seven non-champions, discovers Ambrose Willow, a boxer with the odd condition of bursting into tears the moment he starts boxing. This peculiar trait confounds Costigan and his associate, Joe Harper, but also intrigues them due to its potential as a draw for audiences looking for novelty in the boxing world. Despite Willow's lackluster skills and his melancholic demeanor, Costigan sees potential in him as a box office attraction and takes him to New York for training and fights.

Willow's career under Costigan begins with a fight against Leary, where Willow's weeping disarms his opponent, leading to a knockout victory. The spectacle of Willow's tears draws public interest, turning him into a sensation overnight. Yet, Costigan is aware of Willow's limitations as a fighter and carefully selects his opponents to maintain his draw while avoiding too many losses.

A pivotal moment comes when Costigan and Tom Nelson, manager of Sailor Flynn, a promising boxer, are pressured by a promoter to have their fighters face off. Despite mutual reluctance due to Willow's unusual fighting style, they agree to the match. In the ring, Flynn initially dominates, but the turning point comes when Costigan tells Willow a joke between rounds. The delayed reaction causes Willow to burst into laughter during the fight, startling Flynn and leading to his defeat.