The mafia has decided to expand its gambling business to Florida as well, where however the state laws prohibit such activities. The lawyer Clemente is appointed to find ways of evading the legal loopholes and make the plan possible. Clemente discovers that the Indian reserves of America are exempt from the normal regulations of the States and prepares an action plan: he presents a project for the construction of an enormous shopping centre which, once approved, will instead become the biggest casino in America. An Indian chief, Thomas, opposes the project and is thus killed.

Costello's former opponent, Gonzales escapes from prison and seeks revenge against Costello. He implicates Costello in a criminal case, who even goes to prison, but it soon becomes clear that Gonzales' plan is worthless.

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.

Jack Costello is a private detective in Miami and he finds out he is being followed by a man. He confronts him and finds out his name is Dumas. Dumas speaks with a French accent and he says he is a cartoonist and he needs Costello's image for his cartoon, but with a different name: Extralarge. Wendy is a black petty thief and when she steals an old pocket watch from Senator Pillinger and two men begin to shoot on her she seeks refuge with Costello.

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.

A Chinese scientist comes to the US but is kidnapped straight away from the airport and switched for his look-alike, which soon suffers death in mysterious car accident. Young girl who says she's scientists niece comes to Jack 'Extralarge' Costello and asks him to find her uncle. Extralarge starts investigation, but someone doesn't want him to learn the truth and whole case is complicated even more when he finds out that the girl is not the person who she claims she is.