Kimizuka is approached by Nagisa Natsunagi, a girl with a yearning seemingly inspired by the heart she received in a transplant. When Kimizuka asks Fuubi for help, she takes them to meet an unexpected someone who provides surprising information.

Facing off against Chameleon with Natsunagi’s life on the line, Kimizuka finds that he is not alone in this battle, with help coming in unexpected forms. But against this wily foe, Kimizuka’s allies--and his own resilience--are tested to the limits.