H na Jorei Puzzle! Ikitai Ikasete Reibaishi Kanata no Onegai

Kyousuke is a private detective and (unofficially and reluctantly) an exorcist of ghosts, but since encountering Kanata, a long lost childhood friend, the number of ghost hauntings around him grows to dangerous levels. What's happening? And why all these paranormal events also have erotic overtones?