This sequel follows the story of the first Matt Reeves Batman movie. I wrote a The Batman sequel plot.
After the riddler was detained, a wave of copycats began to appear in the city of Gotham. Of one these copycats are a former Arkham psychiatrist named Johnathan Crane (played by Rami Malek), who is developing a biological agent named “Fear Toxin” and plans on releasing the toxin into the atmosphere to protest against Gotham’s corruption and plunge the city into chaos.