Chapter 3’s title page features a line drawing of a mountain scene. The background of the drawing is marked off into a grid pattern.

Yoshiharu Miura is an art teacher. He works hard to be a good teacher, friend, and family man, but sometimes he likes to go off by himself to hike and camp on a mountain near his home. On one such trip in 1992, he is murdered. Along with his battered body, the police find a drawing of the view from his vantage point on the mountain.

When the student leader of the school art club that Miura supervised is interviewed, she says that Miura was a hot-tempered man who was widely disliked at school. Miura’s wife confesses that she and her husband were not close, as she disliked Miura’s domineering and insensitive parenting of their son. Even Miura’s long-time friend, Toyokawa, has little good to say about the man. Miura, he says, was arrogant and self-involved. Miura used the fact that he had gotten Toyokawa work at the school to pressure Toyokawa into always going along with whatever Miura wanted to do.

Three years later, a young newspaper employee, Shunsuke Iwata, finally persuades his boss, Isamu Kumai, to show him the paper’s file on the Miura murder. Kumai initially covered the case, but he was ill with cancer and had to give it up; the Miura story was the first one he had ever had to stop investigating. All this time later, it still bothers him. Although Kumai is at first reluctant to let Iwata investigate the story, when Iwata explains that Miura was a mentor figure to him in school, Kumai relents.

The documents that Kumai shows Iwata include many diagrams of the information he gathered. These diagrams lay out the timeline of Miura’s movements, the presumed time of his death, the movements of suspects, and so on. Kumai explains that there are three suspects in Miura’s murder: his wife; his friend, Toyokawa; and one of his students, “a young woman named Kameido” (122). On the day of his murder, Miura bought some food at a supermarket near the train station and then picked up Toyokawa. They hiked partway up the mountain together, and then Toyokawa headed back down. Miura continued upward to the place he intended to camp for the night.

In the morning, Miura was found dead, with stab wounds and injuries from being struck over 200 times with a rock. His sleeping bag and the food he had bought were missing from the campsite. Because the autopsy found the remains of his usual lunch in his stomach, still only partially digested, the police concluded that Miura died around five o’clock the previous night, after eating lunch but before dinner. They had no theory about why the killer might have taken away the sleeping bag and the food Miura bought for dinner and breakfast.

The police learned that no one had seen Toyokawa on his way back down the mountain. They surmised that, instead of going home as he said he was going to, Toyokawa secretly followed Miura up the mountain and killed him. They could not find enough evidence to try him for the murder, however.

Iwata looks at the beautiful, detailed drawings that Miura made of a butterfly and flowers that he saw on the mountain. Iwata is surprised by the contrast between these drawings and the hasty sketch that was Miura’s final drawing. Both the earlier drawings and this final drawing appear as illustrations, on pages 135 and 136. Miura’s final drawing is the mountain view that also appears on the chapter’s title page.

Iwata and Kumai can see that the drawing is an accurate view from the place where Miura was camping. It even includes a detail—a recently damaged fence—that proves it was drawn during this particular trip up the mountain. Unlike the butterfly and the flowers, the mountain view drawing is not in Miura’s sketchbook. It is drawn on the back of the receipt from Miura’s food purchases earlier in the day.

Gridlines show that the receipt was folded into squares before the drawing was made. The police concluded that Miura did this to help him accurately reproduce the proportions of each item in the scene. A diagram on page 138 uses a drawing of an apple to show how this process works. Iwata and Kumai are confused by this theory. The fact that Miura used a receipt instead of his sketchbook indicates that Miura was in a great hurry—that, for some reason, he drew the scene when he was “on the verge of death” (139)—making the implied planning an odd choice. Iwata does not think an accomplished artist like Miura would have needed to use grid lines, in any case.

Iwata creates several diagrams of his own, outlining the evidence in the case. Kumai is impressed by his zeal, but he cautions Iwata that it could be dangerous to follow up with interviews, as it risks alerting the killer that Iwata is looking for them. Nevertheless, Iwata talks to Kameido. She explains that she had a crush on Miura and was devastated when he died. She tells him that she believes Toyokawa is the killer. He secretly hated Miura, she says, because although Toyokawa was the better artist, Miura was more successful. She explains that, after Miura’s death, she felt sorry for Miura’s widow and child and spent time at their house helping them. Toyokawa would sometimes come by, and Kameido got the impression that he was making sexual advances on Miura’s widow, who seemed frightened of him.

Iwata tells Kameido that he plans to hike up the mountain on the anniversary of Miura’s death as a kind of memorial. He invites her to join him, but she says that she has to work that day. She offers him her business card, and he learns from it that her full name is Yuki Kameido. Just before he leaves, he sees a gridded product that Yuki has created so that a student who cannot see can participate in drawing classes. He realizes that a possible reason Miura might have folded the receipt was that he was trying to draw the scene without looking at the paper: The grid lines might have functioned as a tactile guide.

On the anniversary of Miura’s death, Iwata recreates Miura’s movements exactly. He buys the same items from the same store and hikes up the mountain at the same time and pace that Miura did. When he reaches the spot where Miura camped, however, he realizes that it has grown far too dark to see the mountain view that Miura sketched. Diagrams on pages 160 and 161 recreate what he sees and show the angle of the sun relative to the height of the mountains.

Iwata has a sudden realization: Miura must have drawn the picture in the morning, intending to leave behind proof of his real time of death. This would mean that the killer arrived in the morning and force-fed Miura the same meal he had eaten for lunch the day before, creating a false narrative about Miura’s time of death. Because both Toyokawa and Miura’s widow had an alibi for the morning hours, Iwata concludes that Yuki Kameido must be the real killer.

That night, Iwata wakes in his sleeping bag and finds that he cannot move his arms or legs. He realizes that someone has tied a rope around the bag. A woman is sitting by his feet; her long hair obscures her face, but he is sure it is Yuki Kameido. The woman raises a rock into the air and brings it down hard on Iwata’s leg. She repeats the motion. Iwata, in terrible pain, hears a bone break. He thrashes around but is helpless to get away. Again and again, she bashes him with the rock.

Iwata passes out. When he comes to, the woman is sitting on his chest. Iwata realizes that this is how Miura died and that Miura must have drawn the mountain scene with his hands trapped inside his sleeping bag. The woman accuses Iwata of trying to interfere with her and Haruto’s happiness, and Iwata realizes that it is not Kameido but Miura’s widow. He is momentarily confused, knowing that she could not have killed Miura in the morning. He realizes that Miura must have drawn the mountain scene at night, from memory, but he cannot understand why he would have done it.

The woman force-feeds him the same meal he ate for lunch earlier in the day. As she begins battering him with the rock again, Iwata realizes that he is going to die. He takes paper and a pencil from his pocket and, inside the sleeping bag, draws his own version of the mountain view.

A newspaper announcement a few days later reveals that Nobu Toyokawa has been found dead, apparently having died by suicide. The word-processed note found with his body, signed with his name, claims that he is the one who killed Yoshiharu Miura.