Norwegian Wood is the story of Toru Watanabe, a young man who is damaged by the suicide of his high school friend, Kizuki. Toru falls in love with Kizuki's tortured girlfriend, Naoko, who is isolated in her own mind. When she goes into a mental hospital, he promises to wait for her. Meanwhile, though, he falls in love with Midori, an open and uninhibited girl who represents life. Toru is filled with guilt when Naoko kills herself, but ultimately he calls out to Midori.

The novel begins when Toru is thirty-seven, remembering the events that happened to him twenty years ago. In high school, Toru, his best friend Kizuki, and Kizuki's girlfriend Naoko are inseparable. They are all bound together by Kizuki. However, Kizuki's suicide throws Naoko and Toru into depression. Both choose to attend colleges in Tokyo, where they can get away from their pasts.

Toru runs into Naoko one day while he is in college, and the two start to see each other every Sunday. They go on long walks through Tokyo. Though Naoko has trouble talking and expressing herself, they spend every Sunday together. On Naoko's birthday, Toru brings her a cake, and they spend the evening drinking wine and listening to music. Naoko talks continuously, but she seems to be avoiding certain subjects. Then she breaks down in tears. Toru makes love to her, but the next day she disappears. Toru writes to her and longs for her but hears nothing for a long while.

When Naoko finally writes to Toru, he learns she's had a mental breakdown and is in a sanatorium. While he waits for her, Toru goes to classes and works, remaining isolated until he meets Midori, a girl who appears and then disappears for days or weeks. He goes to visit her at her family's bookstore, and they share a kiss although each is attached to another.

Toru goes to visit Naoko at the sanatorium, and he shares a day with her walking in a meadow. It's the closest he ever is to Naoko, and she tells him about her sister, who also killed herself when Naoko was young. Naoko asks Toru to always remember her, and Toru asks her to live with him when she gets out of the sanatorium.

After the visit, though, Toru falls in love with Midori. Midori has been through the deaths of both of her parents from brain cancer, and she is exhausted with caring for others. She wants someone who will care for her. Toru does not know what to do when he realizes he is in love with Midori. He asks Midori to wait while he sorts things out with Naoko. However, Naoko takes a turn for the worse. She kills herself, and Toru is flung into a pit of grief, despair, and guilt. Toru travels around Japan, alone with his sorrow. When he finally begins to emerge, he calls Midori from a clouded pit of depression.