Johnny's bulge disappears and is replaced by a long-awaited concavity. Still, he is worried about his health, bursts out defensively one night about his mental haziness, then lashes out at Mount for not releasing him. He also attacks Gunther's book.

Gunther transcribes Johnny's last letter. He wrote a note to the vacationing Frances describing his plans once he leaves the hospital. On May 15, he is checked out of Neurological Hospital. Gunther comments on the largeness of Johnny's brain, which he believes is proportionate to one's intelligence. At home, Johnny holds up decently, but the severity of his illness slowly dawns on him. He maintains an active intellectual life, however.

On May 25, Mr. Boydon, the headmaster of Deerfield, calls and announces that Johnny will receive his diploma because of his extra credits. Gunther and Frances cry, but Johnny tries to look nonchalant. They drive to Deerfield, and Johnny's turbaned appearance is at first unsettling to his classmates. Soon Johnny and his different look are accepted. Johnny acclimates himself to school, even taking a chemistry final exam, though his body is failing. He attends all the graduation events. On June 4, he marches to get his diploma despite his ill health and receives thunderous applause.

The family considers various experimental treatments, but none seem applicable to Johnny's condition. They repeat the earlier treatment—mustard, x-ray, Gerson diet, and possibly another operation, in that order of increasing intensity. On June 12, Johnny is sent back to Memorial Hospital. On June 23, Putnam and Traeger discuss the tumor after a consultation with Johnny; Putnam suggests x-rays. On June 27, Johnny suffers a worse attack of amnesia and the shivers.

Johnny maintains his drive for Harvard, even though he has difficulty feeding himself, and his shiver attacks seem permanent. He sleeps more and is less chipper. Frances visits on a Sunday, and on this day, Johnny regains his energy, enjoying a wonderful day with both parents, reading, and packing his books (mostly science) for his summer stay with his mother. The next day, June 30, Johnny is fatigued. Gunther takes him to Memorial for a last test before he heads to the country. The doctors are not too concerned. At home, Johnny has a bad headache, his most severe pain since his first operation. Morphine is sent to the house after Johnny vomits a caffeine pill. Gunther lies and tells Johnny he got accepted to Harvard. Johnny grows hazier, and Gunther calls Traeger to come over.

Traeger tells Gunther that Johnny is dying from a cerebral hemorrhage. Mount arrives, and says Johnny is even worse than before. After several complications, they transport him to a nearby hospital. There, he is given extensive medical attention, but it is not enough. Johnny goes to sleep and never wakes, dying at 11:02 P.M. His parents touch him.