Content Warning: This novel and guide contain frequent references to suicide.

The narrator of Kokoro is an unnamed university student who accompanies a friend to Kamakura beach during his vacation. The friend is called away, however, and the narrator is left alone in Kamakura. On the beach, he meets a middle-aged man whom he calls Sensei “rather than reveal his name” (23). Sensei immediately grabs the narrator’s attention because he is with a Westerner. The narrator sees Sensei many times over the ensuing days, but Sensei’s “unapproachable air” means that he must carefully select a moment to introduce himself. When they do meet, they develop a strong friendship, but the narrator notes that Sensei remains somewhat emotionally distant. In the future, the narrator will realize that Sensei was sending him “a warning, to someone who was attempting to grow close to him” (30). When both men return to Tokyo, the narrator meets Sensei in a graveyard. They talk about death, and Sensei says that he is visiting “a friend.”

The narrator visits Sensei frequently. He tries to invite himself to the graveyard with Sensei, but Sensei refuses, explaining that he must visit his friend’s grave alone.