Kuroko Tetsuya was asked to deliver a package to a mysterious mansion. It turns out, this mansion isn't normal at all.

Vampires were a thing that was long forgotten, believed to be just a myth, but not all is what it seem. In a small city in the northern Canada, where darkness rules over the sun, creatures suddenly come rushing forth, and soon the city is lost to the creatures of the night. Rated M to be safe and because of dead people

"I hope you learn your lesson, Tetsuya; you belong to me." It's rated M for the (light?) gore, not for lemon.