Three siblings, Shōma, Kanba and Himari Takakura are living together, despite the fact Himari was given only a few months to live by the doctor. The three visit an aquarium to see the penguins, where Shōma buys her a queen penguin hat. However, Himari collapses and later dies in hospital. As the brothers mourn, they are surprised to see Himari suddenly spring back to life and cured of her condition, possessed by a spirit which has decided to extend her life, though she returns to normal when her penguin hat falls off. The next day, the siblings receive a shipment of frozen things, which are later revealed to be a trio of strange penguins that no one besides them can see. Just then, the hat possesses Himari again, explaining that she has extended her life but in exchange wants the brothers to obtain something known as the Penguin Drum. As Shōma sleeps that night, Kanba ends up kissing Himari as she sleeps.