After Zhang Meng put on the pair of earplugs that could "solve the root cause" of the noise, the whole family of the neighbors upstairs died in silence. The police said it was an accident, but late every Thursday night, footsteps came from the ceiling on time. When she discovered that the production date of the earplug box was the day she first called the police, the registered IP address of the seller's account was exactly her own home address. When Officer Li handed over the old diary of the mental hospital, the clock on the wall pointed to Sunday zero for the seventh time. This time, she finally heard her increasingly crazy heartbeat playing in her earbuds.