Over a year after his wife, Ruth, died after slipping on a patch of ice, cantor Ben Gottlieb is suffering a crisis of faith, and is unable to sing. He moves back in with his mothers, Meira and Judith. After getting into a fight at a bar, Ben encounters Carla Kessler, who was his music teacher in elementary school. The next day, Carla comes to one of Ben's classes for boys and girls preparing for their bar and bat mitzvahs. Carla says that she has always wanted a bat mitzvah, but she was a red diaper baby; her parents, who were communists, did not allow her to have a bat mitzvah when she turned 13. Ben agrees to teach Carla and gets a ceremony approved by Bruce, the synagogue's rabbi.
As they become friendly, Ben brings a tape of his own bar mitzvah to Carla's house to watch on her VCR. Carla's friend accidentally gives drugged tea to Ben and Carla, and Ben hallucinates interactions with his younger self. Carla lets him sleep in her son Nat's bed. Ben has been suffering from insomnia since Ruth's death, but he sleeps comfortably in Nat's bed. Nat and his family visit the next day. The family and Ben go out to dinner, but when Carla announces her intention to have a bat mitzvah, Nat objects. He explains that he is a wholesale atheist, and thus he objects to any of his other family members participating in the bat mitzvah, although his wife and two young daughters are supportive of Carla and express interest in helping her.
Judith and Meira have been trying to set up Ben with women, preferably Jewish. These include Bruce's daughter, Gabby, who reads a book Ruth wrote and is excited by its sexual nature. She meets Ben near Ruth's grave and professes her attraction to him; they subsequently have sex.
Carla has a stroke. Nat does not visit her in the hospital, but Ben does. Ben presses Bruce to move Carla's ceremony up to the upcoming weekend. In anticipation of the ceremony, Ben invites Carla to the Gottliebs' Shabbat meal; Bruce, his wife, and Gabby also attend the meal.
At the Shabbat meal, Ben announces that he is in love with Carla. Gabby begins crying uncontrollably. As Bruce and Judith lambast Ben, Carla flees and Meira encourages Ben to go after her. Ben does, but slips on ice and injures his head outside Carla's house. Carla takes Ben inside and treats his wound. He stays at her house that night. Recalling Carla's memory that the first bat mitzvah was performed in 1926 in a home, Ben performs the ceremony the next day in the backyard of Carla's house, and sings with her while she chants her Torah reading.
