The protagonist who works as a translator and the younger brother who was a senior middle school student who lost his parents in an accident a long time ago and lived together. For the two brothers who had a dry relationship that didn’t even greet each other properly, an incident occurred. The younger brother committed suicide. The main character, after going through his brother’s belongings, finds a record of his dead brother secretly meeting people through a secret community app. Through meetings with the app users who were connected to his brother, he approaches the truth surrounding his brother’s suicide.