Interesting story. One gripe: Sequel
? But you even titled it as the first part. Is this really the follow-up to something that I missed?
I believe it has that tag because it's kind of a sequel to Hattori's other yuri work, Heart Gifts, since Shiro and Kuro are both from that series. It doesn't seem like they're gonna be all that important, but... maybe they will be, I dunno.