Directed by Todd Phillips, Joker: Folie à Deux continues the story of Arthur Fleck, who, after the events of the first film, is institutionalized in Arkham State Hospital. There, he meets Dr. Harleen Quinzel, a psychiatrist whose fascination with Fleck evolves into a complex and tumultuous relationship. The film delves into their shared descent into madness, set against a backdrop of musical sequences that mirror their psychological states.