Boston Blackie is a former prison inmate campaigning to outlaw Warden Benton's infamous "Water Cross" torture. Benton, however, is successful in his attempt to have Blackie arrested and returned to the prison, but his evil schemes are ultimately thwarted by Mary Carter, Blackie's girlfriend, who manages to alert the governor.
Blackie is arrested when retrieving stolen gems from a safety deposit box for a friend.
Boston Blackie, in the 11th film of the Columbia series, indulges in some wit-trading with a squirmy spiritualist who deals in blackmail, murder and the occult. "Blackie" out to help his pal, "Runt," recover some jewels, finds himself involved in the homicides, and also finds himself as the prime suspect, and now has to find the real culprit in order to clear himself. So "Blackie,", a man of many talents and already a proved magician from cases past, shows he knows a little bit about dancing skeletons, walking phantoms and spiritualism himself, and holds a séance to unmask the murderer.
It is the Christmas Holidays and reformed thief, Boston Blackie goes to Castle Theater to pick up players who will perform for prisoners that are still in prison. He takes a girl with him who has a brother already in prison. She has visited the prison twice in the month, so is not suppose to visit again. However when the group is completed the girl is included as well as Inspector Farrady. One of the clowns in the show is kidnapped and replaced by a con who wants to get even with two ex-partners. Boston Blackie figures out that a con has replaced one of his clowns but is unable to stop him. Blackie's clothes are stolen and a murder is committed. Of course, the Inspector immediately suspects Blackie of being involved. Now it is Blackie's job to find the killer, exonerate himself and help the girl free her brother.
Blackie is seen leaving a Chinese laundry where the proprietor has been murdered, and must track down the real killer in Chinatown.
Blackie helps the police rescue hostage from an escaped maniac on a killing spree.
A mad scramble for stolen loot ensues after Boston Blackie has prisoners released for work in a wartime defence plant.
Blackie is the natural suspect when an expensive pearl necklace is stolen while he is supposed to be guarding it.
Reformed criminal Boston Blackie is outraged when a judge refuses to grant a pardon for a dying friend. He hires Norine, his now-dead friend's daughter, to get to the judge through his son Rudy. However, things don't work out quite as Blackie had planned.
Blackie receives a call from a friend who asks him to retrieve some money from his apartment and deliver it to him in California. Performing this good deed, he is accused of theft, but is allowed to proceed to Hollywood to help the police find a lost diamond.
After a rare gem is stolen from an exhibition at a posh hotel, Inspector Farraday decides to recruit former thief Boston Blackie to find the stone. Along with his assistant, "The Runt", Blackie focuses his investigation on the hotel manager, George Daley, and his sister, Eileen. Through disguises and ruses, Blackie and the Runt try to trick their way to discovering the thieves.
When a murder occurs on an ocean liner docked in New York, the trail leads to Coney Island and a spy ring.
A murder is committed during the auction of a valuable statue. The prime suspect is Boston Blackie, whose reputation for living on the edge of the law makes him an easy target for the police. When the body disappears, Blackie must find it to prove his innocence.
Gentleman crook Boston Blackie answers a want ad for an expert safecracker placed by Doris Macon, who claims a moral right to the safe's contents. She hires Blackie, and they break into the house where the safe is kept. Blackie blows up the safe just as owner Captain von Hoffmeier returns home. Doris disappears with papers from inside the safe, while Blackie takes phonograph records, which, when played with a special needle, reveal secrets that implicate von Hoffmeier as a German political spy.
Blackie performs in a magic show at a women's prison, which gives an inmate an opportunity to escape.
A girl seeks revenge after a Wall Street broker had falsely accused her father and sent him unjustly to prison.
Boston Blackie Dawson gets some jewels that belonged to the imperial family of Russia. A gang of terrorists is after the jewels.
Just out of jail and vowing to go straight, former jewel thief Boston Blackie, undertakes the reformation of a pretty blonde who has stolen a necklace from a cabaret dancer. He learns that the jewel belongs to the mother of the blonde girl, and the blonde's philandering father gave it as a gift to the cabaret girl. Now, Blackie must find a way to return the necklace to the owner's safe without arousing the suspicions of the girl's family.
While burgling a mansion, Blackie is interrupted by little Joey, who has been awakened from his slumbers. Blackie gently orders the kid to return to bed, but Joey refuses to do so unless Blackie helps him say his prayers. Thus is formed a strong friendship between Blackie and his "little pal," inspiring our raffish hero to rescue Joey's mother Rosemary Theby from a scandalous situation.