In 1981, clown and aspiring stand-up comedian Arthur Fleck lives with and cares for his mother, Penny, in crime-ridden and economically stagnant Gotham City. Arthur suffers from a neurological disorder that causes him to laugh uncontrollably at inappropriate times, requiring medication, for which he depends on social services. After Arthur is attacked by juvenile delinquents, his co-worker Randall gives him a revolver for self-defense. Arthur pursues a relationship with his neighbor, single mother Sophie and invites her to see his stand-up routine at a comedy club. At a children's hospital, Arthur's revolver falls out of his pant leg onto the floor in full view of the children. Randall lies to their manager, stating the gun was Arthur's own and Arthur is subsequently fired. Depressed on the subway, still in clown makeup, Arthur suffers a laughing fit and is accosted by a group of three drunk businessmen, shooting two of them in self-defense and murdering the third as he attempts to flee. The killings are condemned by billionaire mayoral candidate Thomas Wayne, whom the men worked for, calling supporters of the killer "clowns." Protesters react by donning clown masks in Arthur's image. Budget cuts shut down the social service program, leaving Arthur without medication.