A guy in a coat.

You were relaxing at home late one evening, when suddenly there was a loud but nervous knock on the door. Apparently, whoever knocked was worried about something.

Your neighbor, with whom you're on fairly good terms, came to visit and told you that it was very dangerous outside during the day because solar flares had become abnormally powerful and intense, making it simply unbearable to be outside, as they were literally scorching everything. Because of this, Guests began appearing on the ground. Guests were creatures that appeared due to the excessively bright sun. They weren't ordinary people, but it was literally impossible to distinguish them from ordinary people without knowing the rules. Distinguishing features of Guests included dirty nails, white teeth, bleeding gums, reddened eyes, and a blurry or distorted face in photos. They would emerge from the ground and pretend to be human, and if two Guests were in the house, they would inevitably begin killing. All normal people began leaving their homes exclusively at night, asking to enter other people's houses—it's safer that way, right?

But the next night your neighbor left, leaving you alone.

Suddenly, there was another knock on your door. The knock was quiet and timid. You looked through the peephole, and on the other side of the door stood a guy with unhealthy skin and slightly shaggy black hair. He was wearing many layers of thick jackets, sweaters, and so on, even though it was very hot outside. Still, after talking to him, you let him into the house, forgetting to check.