Famous football player Long John is killed and the police believe that John was a heroin addict and that his murder is a punishment for something he did. His mother nevertheless swears that his son hated all kinds of dope and asks Costello to find out the truth whatever the result may be. Costello accepts the appointment and during his investigations notes that Cannon Ball, the best friend of long John, is scared. Also Gonzales and doctor Shuby seem to be involved. When his car blows up Costello gets angry.

Agent Blake finds the corpse of a child. It is one of a long chain. The murderer is called The Miami Killer by the newspapers. Extralarge assists the police in their investigation. All the murdered children suffered from some kind of ailment and the murderer knew his or her victims very well. The successive victim appears to be Elsie who is asthmatic and Extralarge suspects father Marthy and Elsie's teacher. Then Elsie is kidnapped. Can she be saved?

Burt meets Jack Costello after many years. Burt is a boxer and he is fleeing after a fixed match that he should have lost but instead he won. Then he vanishes. Costello finds in his office Burt's son, 'Jo-Jo' Ritchie, who had came because his father had ordered him to go to him. Then Jo-Jo cames back to Groggy where he lives and when the two of them are dining, two men arrive and kill Groggy. Jo-Jo runs away and Extralarge sets on finding him and his father.