This is a side-story that is based on the 'Kuroneko Kareshi' series. The tale follows the relationship between Kagami Yuujin, the older brother of Kagami Keiichi, and his childhood friend, butler, and secretary, Takamizawa Ei.
Yuuji constantly berates Keiichi for taking in "a useless stray cat" and for not marrying someone suitable to ensure the continuation of the Kagami family's superior bloodline. However, is Yuuji truly irritated because Keiichi enjoys the company of Shingo, a regular black cat who can shape-shift, or is he resentful because his own life is unfulfilling?
