Mr. Wise Guy

After living all his childhood in the street, a young boy rapidly notices that crime doesn't pay, leading him to become a policeman. One day, one of his best friends goes to prison for a murder he didn't commit. The policeman tries his best to release the friend by proving his innocence.

The East Side boxing champion Muggs answers a challenge to a fight against the West Side champ but just before the match he is kidnapped. His friend Danny Lyons takes his place and wins the fight, only to have Mugs believe that Danny was responsible for his kidnapping.

Rejected by the Army, Marines, and Navy for being too young, the punks help the war effort by throwing fruit at a shop they believe is owned by a Japanese American. Confronted by him wielding a short sword, the gang decides to come back at night but find him dead.

The gang is friend with a millionaire because they saved him from an agression. However, the gang is suspecting that the man's son was actually one of the agressors.

Muggs is tricked into entering a Civilian Conservation Corps camp by Danny in order to get in shape. Muggs resists and battles with the camp captain and with other campers. He also becomes involved in trying to help one of his friends get out of trouble.

The East Side Kids find a young girl in the apartment of a man who has just been murdered. Believing her to be innocent, they hide her in their clubhouse while they try to find the real killer. The killer, however, used a baseball bat as his murder weapon, and the bat has the fingerprints of one of the gang on it.

After having been framed by gamblers, Muggs is barred from riding in horse races. Snce he can no longer race, he takes up a collection so Ma Brown, who owns the horses won't have her stable foreclosed on. However, one of the gamblers involved in the frame falls for Ma Brwn's daughter, and decides to come clean and confess to the police about the frame. The other gamblers hear about it and set out to shut him up and discredit Muggs and Ma Brown once and for all.

The East Side Kids discover that one of their own, Danny, is torn between staying and school and becoming a boxer, and is getting mixed up with gangsters.

Ordered by a judge to get a job, Muggs McGinnis is hired by wealthy Mrs. Murray, who has a penchant for picking up trouble-prone servants. At an engagement party for Mrs. Murray's spoiled daughter Brenda, Muggs enlists his pals as extra help.

Muggs, Glimpy and the rest of the Kids set about to Americanize affable young French refugee Jean Rogers. But after a disastrous baseball game, Jean is chased out of the neighborhood and told not to return.

Copy boys Muggs and Glimpy investigate a murder. They locate the ex-wife of the murdered man and become convinced she is innocent. They hide her from the police while they investigate.