A socially inept clown for hire - Arthur Fleck aspires to be a stand up comedian among his small job working dressed as a clown holding a sign for advertising. He takes care of his mother- Penny Fleck, and as he learns more about his mental illness, he learns more about his past. Dealing with all the negativity and bullying from society he heads downwards on a spiral, in turn showing how his alter ego "Joker", came to be.