Alias Boston Blackie

In the Christmas spirit, Blackie decides to entertain inmates at his old alma mater by organizing a variety show led by clown Roggi McKay. Roggi drops one of his showgirls, Eve Sanders, because she has visited her prisoner brother too often that month. Blackie kindly allows Eve to tag along despite the setback.

Inspector Farraday and Detective Joe Mathews unexpectedly join the group on the bus to keep an eye on Blackie. Their presence signals official supervision as the troupe travels to the prison. The motive is to monitor Blackie's ever-changing schemes.

During the trip, Joe manages to escape from the prison by tying Roggi up and donning his costume and makeup. Farraday suspects Blackie helped him escape, muddying Blackie's reputation further. The escape heightens the tension and sets the plot in motion.

Blackie heads to Eve's apartment, where Joe arrives soon after and claims he is innocent, naming Duke Banton and Steve as the men who got him to drive to the crime scene. Joe takes Blackie's suit and ties him up, disrupting Blackie's plans for the investigation. The confrontation drives the mystery forward.

Eve arrives and frees Blackie, removing the immediate threat posed by Joe. With the immediate danger resolved, Blackie can refocus on uncovering the truth behind the killings. The alliance between Blackie and Eve strengthens as they continue the pursuit.

Blackie and his sidekick the Runt go to Duke Banton's place, but arrive too late and find only a dead body. Joe enters and claims he did not kill Banton, complicating the allegations against him. The mystery deepens as bodies and alibis collide.

As the police surround the building, Blackie engineers a clever switch: Joe takes Banton's place after Farraday has examined the corpse. The 'body' is taken away in an ambulance, misdirecting the authorities. The ruse buys Blackie time to think and plan.

Blackie is taken into custody but uses his wits to overpower Detective Mathews and slip away by donning Mathews's uniform. He slips back into the pursuit under a concealed identity. The escape demonstrates Blackie's resourcefulness and cunning.

Using information provided by Jumbo Madigan, Blackie figures out that the other robber is taxi driver Steve Caveroni. He plans to trap Caveroni by having Eve pose as a fare to lure him to Banton's hotel room. The net tightens around the true culprit.

Eve poses as a cab fare to lure Caveroni to Banton's hotel room, making him believe he is in control with a gun. Blackie then executes the plan to corner the killer. The tension peaks as the trap closes around Caveroni.

Caveroni, feeling trapped, confesses that he killed his partner and acknowledges Joe's innocence. Farraday and his policemen eavesdrop outside the door, closing in on the evidence. The confession seals the truth of the case.

Caveroni makes a break for it but is shot dead by the pursuing officers, ending the pursuit. With the killer neutralized, Joe is cleared of any wrongdoing and Blackie narrowly avoids capture again. The Christmas mystery is finally resolved.