Ai Natsuki, a daughter from a prestigious family, runs a letter-writing business and has ties to things not of this world, including taking commissions from ghosts. However, one day, she accidentally trips and dies! When she awakens, she finds herself before the King of the Underworld, Taizan Fukun. Realizing she cannot die here, Natsuki works hard in the underworld and, with certain conditions, is resurrected! Her task is to assist Taizan Fukun with his research in the mortal realm. Now revived, she is appointed to serve as a court lady in the royal palace…