Joker 2 continues the story following Arthur Fleck (Joaquin Phoenix) and the chaos he unleashed in Gotham in Joker (2019). At that time, he famously shot talk show host Murray Franklin during a live broadcast.
The shocking incident led to his arrest by the police, but it also sparked widespread riots throughout Gotham City.
Two years later, Arthur Fleck—now known as Joker—is an inmate at Arkham State Hospital, commonly referred to as Arkham Asylum. The facility serves as a psychiatric hospital that houses mentally ill patients who are also criminal suspects.
Arthur is both being treated and detained there while awaiting his trial. The intense public attention surrounding him has turned the upcoming trial into a major media spectacle, often dubbed “The Trial of the Century.”
During this period of anticipation, Arthur encounters a fellow Arkham patient named Harleen Quinzel, better known as Harley Quinn (played by Lady Gaga).
Harley becomes fascinated with Arthur, intrigued by his presence and aura. Her curiosity soon transforms into love—and eventually into an obsession with the Joker.
The two grow close, connecting over their shared madness. They begin to collaborate, navigating the chaos and darkness within Arkham Asylum together.
Their twisted relationship fuels even more madness, as Arthur's followers outside the asylum begin organizing a movement to break him free from captivity.

