Slip and Sach take the rap for a robbery they did not commit in order to uncover the real robbers, whom they suspect are led by a convict who gives orders to his gang outside via a short-wave radio stashed somewhere in the prison.

Leo Gorcey
as Slip Mahoney

Huntz Hall
as Horace Debussy 'Sach' Jones

G. Pat Collins
as Bat Armstrong

Effie Laird
as Ma Armstrong

Bernard Gorcey
as Louie Dumbrowsky

William Benedict
as Whitey, Bowery Boy

David Gorcey
as Bowery Boy #4, dark-haired

Buddy Gorman
as Bowery Boy #5, slender

Joseph Crehan
as Warden Burnside

Richard Benedict
as Skeets O'Neil