Sumnima is a love story between a Brahmin boy, Somdutta and a Kirati girl, Sumnima. Somdutta is devoted to Brahmin rituals worshipping the gods. He practices celibacy and is greatly disciplined. Sumnima is very down to earth and knows how to live naturally. They spend a long time on the Koshi riverside and develop a deep affinity for each other. After their separation, Somdutta knows that Sumnima has become deeply rooted in his heart.
His unexpressed love for Sumnima haunts Somdutta till the end of his life. He comes to think that the sacred education, which was supposed to be a ladder to salvation and austerity, kept him from true happiness and actually experiencing life. He realizes that the false line drawn by religion separates the community into castes, classes and many other divisions. The novel depicts how the restriction of human desires and physical needs can all but ruin a person’s life.