The old laboratory building at Jiangcheng No. 1 High School looked like a stranded whale in the early hours of the morning.
When Li Mo stood at the edge of the sixth-floor rooftop, the rain had just stopped. The concrete railing was only four feet high, with a faded warning sign stuck to it: "No climbing." The sign was rusted, its edges curling up like a malicious smile.
He counted the steps. From the moment he slipped out of the dormitory until now, he had taken 7,321 steps. That number was unlucky, he thought. Seven plus three plus two plus one equaled thirteen.
His math teacher had once said that thirteen was a prime number, divisible only by one and itself. A lonely number, just like him.
