Kudo finds Yusaku sitting on the park bench, distraught by the news that Yukawa has just shared with her about Ishigami’s sacrifice, including the murder of another human being. Kudo offers to take her to a restaurant, but Yusaku is too rattled to do anything. He drives her home and, before leaving, proposes to her, offering her diamond ring. She accepts the ring, promising to give it some thought.

While back in her apartment, she retrieves the three letters that Ishigami had written in order to make himself appear to be a stalker. Included with the letters is a note instructing Yasuko on how to deal with every possible question the police might try to ask her. In the note, Ishigami encourages her to marry Kudo and seek her own happiness. This leads Yusaku to seriously contemplate marrying Kudo, since it would be in accord with Ishigami’s last wishes, even it means having to live with a guilty conscience. In this moment, though, Yusaku receives a call from a teacher from Misato’s high school informing her that Misato has just attempted suicide.

The scene shifts to Ishigami, who sits alone in a jail cell, where he contemplates the scratches and marks on the wall, drawing shapes with them and using them to formulate math problems. He reminisces about a day not to long agon when he attempted to commit suicide. Just as he was about to hang himself in his apartment, Yasuko and Misato knocked on his door, introducing themselves as his new neighbors. Captivated by their beauty, Ishigami found the will to continue living and attributed this newfound will to live to a miracle of fate whereby his encounter with the Yusaku and Misato was timed to save him from suicide.

Far from being a stalker, Ishigami never intruded upon Yasuko and Misato’s lives and was always only ever content with occasionally and accidentally hearing the sound of their voices on Sundays.

Ishigami also recounts how he had executed his murder so to make it look like Togashi had been murdered on March 10. In reality, it was the homeless man whom Ishigami had referred to as the “Engineer” who was killed on that day, just as Yukawa had already determined. Pretending to offer him work as part of a construction project, Ishigami paid the man an advance of 50,000 yen. In exchange, the homeless man would have to stay in the same hotel room that Togashi had stayed in, after which he would have to go to the river as an “observer.” It was then that Ishigami strangled him with the same kotatsu cord that Yusaku used to strangle Togashi. Reflecting upon the facts of the case, Ishigami is triumphant, noting how it would be impossible for Kusanagi and Yukawa to incriminate him. “I won,” he thinks to himself.

Ishigami is jerked out of his rumination when he is told that someone has come to visit him. It’s Kusanagi and Yukawa. Yukawa informs Ishigami that Yusaku had been informed of the truth and that there would be a way to identify the body of the dead homeless men. In spite of Yukawa's admonitions, Ishigami continues to play the role of a stalker, noting that even if the body were identified and Togashi’s corpse found, it will have already been too late. Just as they are leaving their visitation room, Yusaku comes from down the hall and prostrates herself before Ishigami, apologizing for everything. She has made her own confession to the police already and insists to Ishigami that she ought to take responsibility for actions. Upon hearing this, Ishigami cries out in anguish.