This is the country of Vampires, "The land of the night" In a country where the sun only rises once every 100 days, one vampire named "The Ancestor" rules. Tonight, five young promising vampires are gathered to the castle. When they have gathered, "The ancestor" delivers this message. "There is a human hunter amongst us. He is after my life. Find him"

"To those of you who lack the courage to die alone. Shall we die together? I'm waiting for those who are interested to contact me." Date: XX Month, 20XX. Somewhere in Tokyo. - Inspired by a post on a certain social media, six people seeking to end their lives gather. At the arrangement of the organizer of the suicide meeting, they will have a final dinner before leaving this world together before dawn. However, it turns out that the six cannot die together; the organizer is discovered as a corpse. Did the organizer commit suicide? Or... was the person murdered? Amid various speculations, the remained five begin to debate.