Lin Shen, 28, is the night shift manager of a 24-hour convenience store in an urban village. Life is divided between two things: working in stores at night and sleeping in a cramped rental house during the day. He is taciturn, and his only habit is to record the sales data of each product in the store, and he has kept a notebook for seven years.
Late one night, a "Natural Disaster Warning: A polar day-level geomagnetic storm will arrive in 72 hours and the duration is unknown" popped up on the phone. Everyone thought it was a prank, but Lin Shen noticed that the sales of bottled water and compressed biscuits in the store had increased dramatically in the past three months - someone was stocking up in advance.
He took out his notebook and drew three curves: sales volume, frequency of abnormal weather, and the "strange things" he recorded - the ground was hot with water, and flocks of birds fell on empty streets late at night. The three curves converged at a terrible point three days later.
Lin Shen didn't try to notify anyone. He closed the convenience store, locked the door, and began to implement a long-prepared plan: to transform the three underground floors of an unfinished building in an urban village into a shelter. But someone noticed him—the back figure dragging cement and steel bars in the middle of the night, and the notebook full of curves.
When the natural disaster struck, Lin Shen discovered something: this notebook recorded not only data, but also some things that he still dared not admit - for example, three months ago, he saw a person in the store who was about to die in a natural disaster. And the man was dead before he walked into the convenience store.
