The story begins with a wealthy and unscrupulous banker named Favraux, who is threatened by a mysterious avenger known only as Judex. Judex sends a letter to Favraux demanding that he confess his crimes or face dire consequences. Favraux dismisses the warning, only for Judex to make good on his promise, leading to Favraux's apparent collapse during a lavish party. In the aftermath, Favraux's daughter Jacqueline discovers that her father has been hiding a double life filled with deceit and betrayal. Unbeknownst to her, Judex, serving as both avenger and protector, keeps a close watch to ensure justice is served.

As Jacqueline grapples with the revelations about her father, other sinister figures emerge from the shadows, further complicating the unfolding drama. The elegant and enigmatic Diana Monti, along with her accomplice Morales, have their own designs on Favraux's fortune, creating a web of intrigue and danger. Jacqueline finds herself enmeshed in schemes that threaten her safety and sanity. Throughout this labyrinth of deception, Judex's true motives and identity are gradually revealed, as he orchestrates a complex game of retribution and redemption. The narrative weaves through themes of justice, vengeance, and the power of masked identities, culminating in a tense and gripping conclusion.