High school student Yasaka Mahiro is suddenly attacked by a monster one night. The one who comes to rescue him is the silver-haired beautiful girl Nyarlathotep (nicknamed Nyako), who claims to be one of the outer gods in the Cthulhu mythology. As an alien, she is the "faceless god" in mythology who can change her appearance freely. Because other aliens are about to attack Mahiro, she was sent to Earth to protect him, and then they began to live together.