What's Moon Phase?

[sodatoonami]

Could anyone tell me wat Moon Phase is, because everytime I see the comercial it makes it so INTERESTING.So i'd like to know wat it is. Thanks.:D

[小美ドクロchan]

It is a vampire show concerning a little girl named Hazuki and a college student named Kouhei. Hazuki tries to make Kouhei her slave by biting him but he is immune to the bite.