Sonar Pahar is about Upama, who is in her 70s, doesn't share a healthy bond with her only son Soumya. Soumya's childhood friend Rajdeep along with his seven-year-old son Bittu happens to visit Upama. As days pass by, Upama and Bittu get very close to each other and further, the plot explores the bond between children and the elder ones whom they are close to. The film also highlights the complexities that are often seen in families due to the generation gap.