After the Glen City sheriff runs him out of town, boxing promoter Dan Muldoon convinces his old friend Grey Holden to host a prize fight on the Enterprise. When Grey Holden knocks out Muldoon's fighter, The Dublin Boy, by accident, he is forced to take the young man's place in the ring or he'll have to return the gate receipts to a boat-full of angry passengers. Meanwhile, a couple of thieves plan to steal all the money that has been wagered on the bout.
—David Bassler