Arthur Fleck works as a clown and is an aspiring stand-up comic. He has mental health issues, part of which involves uncontrollable laughter. Times are tough and, due to his issues and occupation, Arthur has an even worse time than most. Over time these issues bear down on him, shaping his actions, making him ultimately take on the persona he is more known as...Joker.

Jack is a shy and awkward man who drives a limo and lives an unassuming life. His friend and co-worker, Clyde, and his wife Lucy, feel sorry for Jack and set him up on a blind date with Connie. Connie shares Jack's shyness and awkwardness, but through each other they seem to be able to find solace within themselves. Trouble might be brewing in paradise though, as Clyde and Lucy's marriage stumbles just as Jack and Connie's relationship grows.