Kirin, a loner, is approached by Kaito Nova, who claims to be his childhood friend's grandfather and a member of the prestigious Nova clan. Kaito offers Kirin the opportunity to be adopted into the declining Arch-duke household and become its next heir, revealing they share same bloodline,Despite initial reservations, Kirin accepts, hoping to honor Kaori's memory and find a sense of belonging.in the world. But things are way complicated than he initially thought, since the clan had been in decline after all the heirs were assassinated.