he lead character was Frank Kennelly, the Captain of the 21st precinct. He was portrayed at different periods by actors Everett Sloane, James Gregory, and Les Damon. Kenelly was also called Captain Cronin during Gregory's time. Other stars in the series included Harold Stone as Sergeant Waters, Santos Ortega as Lieutenant Gorman, and Ken Lynch. It focused on a specific police unit located on the city of New York.

The series was based on true police stories, just like Dragnet, which aired before it. It became immensely popular during its run, as the listeners were eager to learn about the true-to-life police stories.