Arthur works as a clown in the morning and as a stand-up comedian at night. He quickly realizes that the joke is on him, not what he says or does. His uncontrollable laughter that bursts out at the wrong moments proves that he is unable to sync with his audience. The more he tries to control the situation, the more he ridicules himself and leaves himself exposed, even to incidents of violence. As he moves in an existential vicious cycle, between reality and madness, one wrong choice is enough to trigger a chain reaction of escalating and, ultimately, disastrous events.