Anzu Murata, assuming the false name of Shizuka Yamauchi, sneaks into the Mitarai household under the guise of a housekeeper in order to ascertain the truth behind the fire 13 years ago — a fire for which her mother took all the blame. Selling herself to Makiko, the hard-to-please second wife of her father, Dr. Mitarai, she continues scouring the Mitarai household for clues as she gradually gains Makiko's trust. Her real identity having been deduced by Makiko's older son, Kiichi, Anzu finds herself in a dilemma when Kiichi offers her a surprising overture: "I'll tell you what happened on the day of the fire." What could his true intentions be behind this?!