An immortal vampire, Kagamihara Machi, is roughly 600 years old and originally from the West. She arrived in Japan during the Sengoku period and has lived there ever since, hiding her true nature. Human life is heartbreakingly short; every few decades she makes wonderful friends only to watch them grow old and die, leaving her alone. To cope with the crushing loneliness and boredom, Machi adopts a strategy: she joins a different university club every four years, treating each four-year cycle as a fresh social start.

The story follows her daily life as a university student who conceals her vampirism while navigating friendships, parties, and the mundane challenges of youth. Her routine is disrupted when another vampire, a young woman named Kiribana, appears and aggressively tries to recruit Machi as her ally. Kiribana is baffled by Machi’s refusal to drink human blood and her insistence on living quietly among mortals. Machi just wants to be left alone, but she soon finds herself targeted by other hostile vampires as well, including a male attacker who forces her friends to step in and protect her.

Over the course of the series, Machi’s carefully maintained boundaries are tested. She must balance her desire for normal human connections with the supernatural world that keeps pulling her back. The narrative is driven by arcs of friendship, conflict with fellow immortals, and the gradual revelation of Machi’s long history in Japan, culminating in a situation where her centuries-old past threatens to be exposed when a friend’s grandmother recognizes her from decades earlier. The story concludes with Machi learning to reconcile her identity as a vampire, a monster, and a human among humans.