The Batman movie explained
Halloween was celebrated by Gotham City mayor Don Mitchell Jr. is killed by a killer who goes by the moniker "The Riddler.". Along with the Gotham City Police Department (GCPD), billionaire Bruce Wayne, who has been operating as the vigilante Batman for two years, conducts investigations. The Riddler left a message for Batman, which Lieutenant James Gordon finds out, but commissioner Pete Savage chastises him for letting a vigilante into the crime scene and orders Batman to leave. After killing Savage, The Riddler leaves Batman with yet another letter. Batman and Gordon learn that the Riddler left images of Mitchell with a woman named Annika at the Iceberg Lounge, a nightclub run by mobster Carmine Falcone's lieutenant Penguin, on a thumb drive that was left in Mitchell's car. Batman confronts the Penguin, who claims ignorance but is caught by the fact that Selina Kyle, Annika's roommate and girlfriend, is a waitress there. Batman sends Selina back to the Iceber...