She wanted to be a doctor. She had wanted to be a doctor since she was nine and her grandmother had a stroke and Noor had sat in the hallway of Mercy Regional and watched a neurologist with a gray braid explain to her father, very slowly and very kindly, what had happened inside his mother's head. Noor had understood almost none of it at the time and had wanted, more than she had ever wanted anything, to be the one who understood. She was taking AP Bio and AP Chemistry and AP Psych. She volunteered Saturday mornings at the hospital gift shop, which was not medicine, but was the building. She read things. She was, she knew, the kind of person who would read forty pages of a pediatric neurology review at eleven at night with a highlighter, and she had done exactly that, the second week of October, and come away more frightened than before.
And then, in AP Chemistry, the new kid had turned in a lab report.
It was the titration lab, a nothing lab, and Mr. Mahlke had graded them and handed them back and as he passed Noor's desk he had stopped, and set the new kid's report down next to hers, and said, "Castellano, you two should compare conclusions, you both did the error analysis the long way," and moved on. Noor had looked at the report. On the back page, in the margin, Imre Yusuf had drawn, absently, the way people doodle, a small careful diagram of a human brain in cross-section, with the corpus callosum labeled, and next to it, in tiny block letters, a list: HA. PHOTO. SLEEP. IRRIT. MEM.
She had looked at that list for a long time. Then she had turned around in her seat and looked at Imre Yusuf, who was looking at his own hands, and she had thought: headache, photophobia, sleep disturbance, irritability, memory. She had read that list in four different places in the past two weeks.
She had caught him at the bike rack after school. She had not been subtle. She had said, "Why do you have post-concussion symptoms written on your chem lab," and he had looked at her the way he looked at everything, with a slow, quiet attention, and said, "Why do you know what they are?"
That was eleven days ago. That was how it started.
Imre Yusuf's older brother was named Bastian, and he was twenty-one years old, and he lived in the bedroom across the hall from Imre's in a rented split-level on Birchmont Avenue, and on good days he made pancakes.
Imre told her this on the second afternoon, sitting on the low concrete wall behind the science wing where the buses idled, with his backpack between his feet. He told it the way he seemed to tell everything, in order, without decoration, as though he had told it before and had learned which parts people needed and which parts only made them uncomfortable.