Lester Grimm is a young man who has always struggled with trusting his girlfriends due to a traumatic experience he had in his teenage years. When he meets Ramona Ray, he is immediately smitten, but his insecurities begin to get the best of him when he learns that her ex-boyfriend is the successful novelist Dashiell Frank.
Determined to find out more about Ramona's past with Dashiell, Lester starts attending the same group therapy sessions that Dashiell attends. He disguises himself as someone who also has issues with jealousy, hoping to learn more about what happened between Ramona and Dashiell.
As Lester becomes more involved in the therapy group, he begins to develop a friendship with Dashiell, which complicates things further. Lester starts to see that Dashiell is not the monster he had imagined him to be, and that his jealousy may have been misplaced.
Meanwhile, Ramona begins to sense that something is off with Lester and grows increasingly frustrated with his behavior. She tries to get him to open up about his feelings, but he is too afraid of what he might learn. Eventually, everything comes to a head as Lester's jealousy reaches a breaking point.
Mr. Jealousy is a quirky, darkly comic film about love, trust, and the human psyche. It explores the depths of jealousy and insecurity and asks whether it's possible to overcome these emotions in a healthy, mature way. The film is directed by Noah Baumbach, known for his films The Squid and the Whale and Marriage Story.