When rookie policeman, Han Jisung, gets multiple invitations leading him to locations of murders, he tries to use them to catch a serial killer, known as 'Crane'. However, this is easier said than done. No matter what he tries, Crane is always a step ahead of him and Jisung is getting closer and closer to the point of giving up. However, when a university professor, Lee Minho, begins to interfere in Jisung's investigations, Jisung finds a new way to read the invitations. With Minho's help, Jisung finds himself looking at things differently, bringing him closer to the answer he's been trying to look for this whole time. ⚠TW: Maybe some descriptions of blood and mild violence