Mana, Karina, Naoto, and Yuuki are high school students and childhood friends living in a world where it is permissible to own "pet humans." Their ordinary lives take an unexpected turn when Karina introduces an 8-year-old boy, restrained and collared, into their home as a new "pet human." Despite his human appearance, he exhibits animalistic qualities. The situation becomes even more complex the following day when they receive the shocking news that Yuuki, one of their own, is also a "pet human."
