When Shao Boqing rang the doorbell, Nina was sleeping like a log. She thought it was the alarm clock, so she fumbled her hand to the bedside table with her eyes closed and pressed the button at random. But the noise still kept coming. She threw the alarm clock out angrily. The metal shell fell to the ground and made a loud sound. Only then did Nina wake up slightly and half opened her eyes.

The noise stopped. Nina looked at the alarm clock on the ground and frowned in confusion. ...