The controlling "Dom" and the dependent "Sub"--these are "the second genders" of the vampires.
When vampires of two different second-genders meet, they can establish a "bond contract".
Located in a spacious land in a mountain recess is "Eclair Gymnasium Academy", a school where young vampires experience youth. The academy teaches its students about "bond contract" and requires them to find someone to be their contract partner for a limited amount of time.
With the goal of sealing a "bond contract", blood leads these students to their fated pairs...
