

Nadia had been best friends with Oz for six years, which meant she knew exactly when he was lying.
His left eyebrow did a thing.
It was a very small thing, barely a twitch, but she had catalogued it over six years of friendship and it was one hundred percent reliable. The eyebrow had betrayed him over a stolen biscuit in year three, a forgotten birthday card in year five, and approximately forty-seven smaller incidents in between.
The eyebrow was doing the thing right now.
"I just like this hoodie," Oz said. He tugged the hood further down over his face. They were sitting in the school canteen and he had not taken the hoodie off since arriving that morning, which was strange because the canteen was warm enough to grow tomatoes in.
"It is September," Nadia said. "It is twenty-three degrees outside. You are sweating through that hoodie as we speak."
"I run warm," Oz said.
"You definitely do not run warm. Last February you wore shorts to school and told the PE teacher you were climatically resilient."
"That was different."
"Oz." Nadia put down her fork. "What is under the hoodie."
"Nothing."
Left eyebrow. Definitive.
"Is it a costume?" she asked.
Oz choked on his water. "What? No. Why would it be a costume?"
"Because," Nadia said, picking her fork back up calmly, "three times in the last two weeks you have disappeared for between twenty minutes and two hours, come back with leaves in your hair and what I can only describe as a heroic expression, and the local news has started reporting on someone called the Blue Blur who keeps showing up at accidents and emergencies around town." She speared a piece of pasta. "Also you run very fast now. You did not used to run very fast."
Oz's mouth opened. Then closed. Then opened again.
"The Blue Blur," he said finally, "wears blue. This hoodie is grey."
"Oz," Nadia said.
"It is a very dark grey," he said. "Almost blue, some might say."
"Oz."
He slumped in his chair. The hood fell back slightly. Underneath it, just visible at his collar, was the edge of something that was, unmistakably, blue.
"Oh," Nadia said. "Oh, you absolute disaster."