Blackie goes after a gang that used a bazooka to rob an armored car, and then killed a cop who was a friend of Blackie's during the getaway. The only clue he has is that the the money was scorched by the bazooka's blast.
Blackie tries to clear an ex-convict who's charged with murdering a man in a restaurant phone booth. During his investigation he discovers that the restaurant is actually a front for a counterfeiting ring.
Blackie tries to help a man who is so desperate to get money for his child's medical bills that he's hired a hitman to kill him so the child will get the life insurance money.
Blackie helps Inspector Farraday try to find out who planted a bomb in his Dictaphone and took a shot at him. He soon finds that someone has planted a bomb in his own car.
When the plans for a new metal being developed by the government are stolen, Blackie and Inspector Farraday butt heads over the best way to recover them.
Mary gets Blackie to help the husband of a friend. He turns out to be a man who was killed by a poisonous dart from a blowgun. After Blackie begins his investigation the wife is killed the same way.
When a wealthy man out riding his horse in the park dies of a heart attack, Blackie suspects that it may have actually been murder. His investigation uncovers evidence that points toward the man's gold-digging fiancée.
Two sisters stage a series of robberies and, with the help of their henchman, commit a couple of murders. Blackie is on their trail after they kidnap Mary.
A businessman is murdered and his secretary finds out who the killer is. However, instead of turning him over to the authorities, she tries to blackmail him with an incriminating Dictaphone cylinder.