A genetic curse that masquerades as disease, passed down through blood like inheritance itself. Kazuna and Chizuna don't fight their condition, they carry it, together, in the unbearable quiet between episodes. The show moves slow enough that you feel the weight they're feeling, and four episodes somehow contain the entire architecture of a family tragedy.
Kazuna has lived peacefully with the Eda family for years, unaware that his blood runs with a hereditary curse. When hunger begins to consume him in ways he cannot explain, he discovers the truth: his family carries a disease that transforms them into creatures of insatiable bloodlust. The realization shatters his carefully constructed life, but worse is learning that his older sister Chizuna suffers from the same affliction. Unlike Kazuna, she has spent years battling her instincts, learning to survive with the weight of constant temptation pressing down on her mind and body. Now reunited, Chizuna becomes both guide and mirror for her brother. She understands what he faces because she lives it every day. Yet her attempts to help him control the sickness reveal something darker: the toll this burden takes on the human psyche cannot be easily shared or eased. As Kazuna struggles to remain himself while something primal claws at his consciousness, brother and sister must confront whether some inheritances can ever truly be overcome, or if they are simply doomed to repeat the suffering that came before them.