Judex

Banker Favraux, rich from swindles and blackmail, receives a note signed 'Judex' demanding he return the swindled money to the victims. The threat unsettles him and foreshadows Judex's growing reach over his affairs.

Favraux hires private detective Cocantin to watch him during a party where he plans to announce his widowed daughter Jacqueline's engagement. Cocantin's presence signals that the house will be under scrutiny and that Judex is already orchestrating events behind the scenes.

Diana Monti is revealed to be Alice's governess and a cat burglar seeking Favraux's fortune. She refuses Favraux's proposal to be his mistress and forces a marriage instead, planning to murder him after the wedding.

Judex, with his assistants, keeps a close watch on Jacqueline as the engagement approaches. He works from the shadows to guard the family and to monitor Diana's moves.

The engagement party features masked guests and a bird-headed magician who performs tricks; the man behind the bird mask is Judex, using the illusion to keep an eye on Jacqueline.

As Favraux begins to reveal the engagement to Diana, he collapses and seems to die of a heart attack. The scene also suggests he has been drugged, complicating the apparent death.

At Favraux's funeral, Jacqueline discovers a letter from Judex and realizes her father’s illegal methods. She renounces most of her inheritance, offering only a portion to support her granddaughter Alice.

That night, Judex retrieves the apparently dead Favraux from his coffin, reveals he is alive but drugged, and imprisons him in an abandoned castle.

Diana makes several attempts to abduct Jacqueline, but Judex foils each attempt. The family remains under Judex's protection as the plot thickens.

Diana shifts to trying to abduct Alice, but detective Cocantin and others intervene, thwarting her plan. The rescue efforts reinforce Judex's control over the situation.

Despite being alive and imprisoned, Favraux becomes despondent over losing Diana and commits suicide. His death removes the threat he posed and clears the path for Judex's next moves.

Diana flees to a building's rooftop where Judex battles Diana's accomplices; Daisy, a circus acrobat, scales the exterior to join the confrontation and close in on Diana.

Daisy confronts Diana on the rooftop and, after a tense fight, Diana is killed. The pursuit of justice culminates in her demise as Judex watches over the resolution.

Judex and Jacqueline are finally reunited and walk along a beach as the film closes with a reflective title honoring a difficult era.