Naples, 1959. Pure Mathematics professor Renato Caccioppoli, Bakunin's grandson, is a tortured soul. Recently discharged from the psychiatric hospital, left by his wife, and increasingly disillusioned with academia and the Communist Party, he lives his last days with painful detachment.

In this dark comedy, a dentist becomes obsessed with the concept of ugliness and goes to extreme lengths to pursue his macabre interest. As he dives deeper into the murky world of his fixation, he discovers the true meaning of beauty and ugliness.

Saturday, Sunday & Monday follows the story of a tailor and shopkeeper in Naples, Italy, and explores the complex dynamics and relationships within their family. The plot revolves around themes of unrequited love, extramarital affairs, jealousy, and the intricate web of family relationships. As the story unfolds, it also delves into the themes of marriage, father-son and mother-son relationships, and the bond between grandfather and grandson. The film captures the essence of Naples and portrays the city's vibrant theater scene, featuring a filmed-play adaptation. Based on a play, it showcases the everyday events and struggles of the characters and how they navigate through life's challenges.