What is the name of this manga?

Okay, a long while ago I read this manga where a boy is a zombie fanatic and goes to this abandoned warehouse place to try and bring back his dead dog to become a zombie. While he is trying to do this, there is a girl that comes by and just starts yelling out loud, because her father is overprotective of her, since she is in a rich family. He notices her ranting and just listens in, and she eventually finds out he is there, and decides to try and help him with the dog. All of their attempts fail, and with the last serum they made, she snatches it and gets caught by her father while sneaking out, and just downs the serum, and eventually she dies and becomes a zombie herself. The boy takes care of this girl, for a while, and tries to stop the decay of her body, considering she is dead.

Anyone happen to know the name of this manga? I can't seem to remember D: