Ayaka Kisaragi is a beautiful woman descended from a long line of Japanese exorcists. However, bored with their traditions, she started her own business, Phantom Quest Corp. The headquarters of the company is Ayaka's quaint little family home, nestled between the skyscrapers of Shinjuku, Tokyo. Along with the traditional knowledge she possesses, Ayaka also uses very unconventional weapons while attacking ghosts and demons, including a lipstick case that turns into a laser sword and earrings that explode into spiritual energy.

Although Ayaka is very competent with her skills, her own bad habits (overindulgence in sake, karaoke, and shopping binges) often cut into the company's meager earnings and interfere with paying the various experts whose help she usually depends upon. Also, because of her drinking, she often sleeps in bed late, which her partner and business associate Mamoru Shimesu has to find creative ways of waking her up. Along the way, and with a little help from various spiritual specialists, Ayaka can usually be found battling vampires, poltergeists, and cutthroat competitors bent on driving her out of business.