The Last Man on Earth Heard the Knock on the Door

In the third year of the end of the world, Zhao Lai, the last man on earth, was repairing cracks in a building he named "Teacher Peach Valley". There was a knock on the door. Three long and two short. A rhythm that he had typed countless times before when he was bored. From then on, express boxes began to appear regularly at the door: endless amounts of instant noodles, a compass pointing to the aquarium, and notes with handwriting that became more and more familiar. Zhao Lai held the pot of cactus "Zhazi" with arms and legs painted on it, rode on a modified tricycle and set off. He didn't know who was knocking on the door. But he was sure that the man owed him three hundred yuan and had owed him three hundred yuan.