Now, the exam was in six days.

His father came home from work, loosening his tie. He peeked over Youssef’s shoulder. “Radioactivity? You’re mixing uranium decay with coffee stains?”

It was the last week of May, and the air in the small Tunisian apartment was thick with the smell of strong coffee and anxiety. On the kitchen table, a massive, spiral-bound notebook lay open. On its cover, written in bold blue ink, were the words: .

He turned to the last empty page of the notebook. Above the printed formula for Énergie mécanique , he wrote one sentence in shaky handwriting: