In a dystopian world monitored by
Batman, a young child grows up in
Smallville, Kansas, idolizing the performers on a sketch comedy program,
UCB Live. The protagonist's mother is disturbed when her child asks, "Was I born in the wrong body?" and immediately books a session with
Dr. Crane of
Arkham Asylum, who prescribes Smylex: a drug that forces its users to put on a happy face, even if they feel depression, anxiety, or
gender dysphoria. Fifteen years later, the protagonist has grown up and moves to
Gotham City to join the cast of
UCB Live, designated as a "Jokeman" by a computer, who will be allowed to have an individual identity in the cast, unlike the women, who are all assigned to be nameless Harlequins that serve as back-up dancers. The process to become on-air talent includes paying $15,000 and enduring
improv comedy classes from
UCB cast member
Ra's al Ghul. The protagonist strikes up a friendship with
Oswald Cobblepot, another struggling comedian who cannot afford the entrance fee and the duo decide that they will instead make their own comedy troupe. To avoid rules that outlaw unapproved humor, they will call their act "
anti-comedy". They set up at a dilapidated carnival and are quickly joined by a number of
law-breaking comedians with their own deliberately unfunny and uncomfortable acts. One of these is
Jason "Mr. J" Todd, who dresses as
a Joker of his own and tells Marxist
observational humor. Mr. J and the hero immediately strike up a bond and go on a date that includes Mr. J's confession that he is a
transgender man, and has previously escaped an abusive relationship. This helps encourage the protagonist to articulate that she is a
transgender woman and the two plot to have her dive into a vat of
estrogen to
gender transition. A retired Batman appears to stop them and it leaves Mr. J shaken. Mr. J reveals that his ex is Batman, who adopted Mr. J and trained him as his sidekick
Robin. He later assisted with a gender transition to the identity of Jason Todd, but their relationship became toxic and sexual. The protagonist takes the name of Joker the Harlequin: a woman with a comedic identity of her own who is trying to be happy but is stuck in the abusive and self-sabotaging patterns of Mr. J. When Joker is breaking up with Mr. J and hacks into a broadcast of
UCB Live, daring producer
Lorne Michaels to let her host instead of Batman, Michaels agrees. In order to host, Joker has to go through a rapid-fire comedy training course with Ra's al Ghul, who teaches her that she is destined to be the People's Joker who makes comedy legal again. On the night of the show, Michaels pumps Smylex into the crowd to ensure that they laugh no matter what Joker says and she finally has a moment where she understands what she needs to be happy and how it cannot come from validation from outsiders. She materializes in the
Fifth Dimension alongside the powerful
Mx. Mxyzptlk who offers to rearrange the time stream for Joker. She asks that her old friend Oswald be given the fame and power of Batman. For herself she only asks to have one happy memory from childhood: she has a vision of 1992, riding in the car with mom, as they sing along to "
The Joker" and laugh. After the credits, the audience are told that Joker will return in ''The People's Nightmare: Freddy vs Joker'' and the glove of
Freddy Krueger appears on screen. == Cast ==