The main character Setsuya woke up in a mansion with an injury on his head and he had lost all of his memory. Then he met his aunt Aoi and the four maids Kasumi, Rika, Miki and Sayaka. Through their story, he learnt that he is the head of the wealthy Shijou family.

And the story began, Setsuya took on a quest to find his forgotten past and reveal the mystery of the mansion as well as the secret of Shijou family ...