女子高生の水埜蝶子は素人ながらも小説執筆に没頭し、その世界に浸ることが多かった。
そんなある日、世間を賑わせている殺人鬼・キラーバリスタの話を耳にしたことで、彼女の日常が非日常になっていく。
The story of “Thanatos’s Bookmark Serial Killer and Literary Girl” begins with a scene called “Killer Barista”, in which a serial killer who routinely drinks coffee after killing his victims is the talk of the town. Aside from high school friends who are excited to say, “It’s a handsome murderer with a fashionable and sweet mask !!”, Choko Mizuno, a literary girl who is aiming to become a novelist, said, “But I have no pride.” If you kill a person and the purpose is robbery, it’s thin as a murderer. ” However, one day, a contact was made between Choko and the killer barista …