After Slip is drafted into the Marines, the rest of the gang volunteers so they can be with him. Sach discovers that the colonel knew his father and he is promoted. During a drill that he is putting the rest of the gang through, they find a soldier left for dead on the side of the road. Slip discovers a playing card next to the marine and traces it to Jolly Joe Johnson's gambling house. They suspect that the gambling house is cheating and set out to uncover the proof.

A police detective uses his girlfriend to track down a homicidal maniac.

As novice detectives, Bud and Lou come face to face with the Invisible Man.

When a Texas playboy is murdered in a New York City nightclub the Falcon investigates. When he learns that the victim was slipped rattlesnake venom, the trail leads to Texas, his own kidnapping and near death.

In 1903, Doctor Huntington Bailey meets a friendly older lady during a train trip. She tells him that she is going to visit her brother Nick and his lovely young wife Allida. Once in New York, Bailey hears that his train companion suddenly died. Shortly afterward, he meets the strange couple and gets suspicious of Nick's treatment of his wife.

After a former model is drowned in her bathtub, Detective James Halloran and Lieutenant Dan Muldoon attempt to piece together her murder.

A warden and his assistant clash over prison reform, triggering a violent riot.

Losing his memories of the last few days, neurologist Dr. Steele is told that his wife has been brutally murdered. Steele, aware of his conniving wife's infidelity, believes he may have been the killer and enlists the aid of his pretty nurse Stella to hypnotize him into recovering his lost memories.

While watching from her train window, Nikki Collins witnesses a murder in a nearby building. When she alerts the police, they think she has read one too many mystery novels. She then enlists a popular mystery writer to help her solve the crime on her own, but her sleuthing attracts the attentions of suitors and killers.

An innocent trucker takes it on the lam when he's accused of robbery.