Siddhartha (don't call him Sidd; he hates that) grows up in a prosperous Brahman family. He’s well-loved, but unhappy despite his popularity. He is spiritually dissatisfied and believes the elders in his community have nothing more to teach him. Siddhartha decides to join the Samanas, who are a group of wandering ascetics. His best friend, Govinda, accompanies him, and the two men spend three years with the Samanas learning how to withstand pain and hunger in an effort to flee the body’s limitations.
Although the two friends learn quite a bit from the Samana way of life, they are still dissatisfied and decide to hear the teachings of Gotama Buddha. Govinda is impressed and chooses to join Gotama’s community of monks. Despite Govinda’s urgings and despite recognizing Gotama as the Holiest Man Ever, Siddhartha opts not to follow Gotama. He decides instead that he’s an independent learner and is done with doctrine. The friends part ways.
Siddhartha travels to a nearby town where he is entranced by the beauty of a well-known courtesan named Kamala. He offers himself to her as a student in the art of love, but is gently rebuffed. Kamala says he needs money, clothes, and shoes. Siddhartha begins working for a wealthy merchant named Kamaswami and becomes Kamala’s lover. For a time, Siddhartha is content with his life and is able to maintain a Samana-like distance from material concerns. Eventually, however, wealth and lust prove too much for Siddhartha. He develops anxiety, self-hatred, and a high-stakes gambling habit. One morning, overwhelmed by his own depression and troubling dreams, Siddhartha walks out of his fancy home and never returns.
After considering suicide and briefly encountering his old friend, Govinda, Siddhartha finds a ferryman and asks to become his apprentice. The ferryman, named Vasudeva, accepts Siddhartha as his companion and together the two men listen to the river. With the river as a spiritual guide, Siddhartha gradually grows wiser and wiser. After allowing his son (by Kamala) to leave the river and follow his own path, Siddhartha achieves enlightenment. Vasudeva passes into Nirvana, and Siddhartha continues to ferry people across the river. He then helps Govinda reach enlightenment.