After being kicked out of their apartment because they were unable to pay the rent, orphans Arakwa Chiyou and her mute brother Keiichi have nowhere to live. Wandering around aimlessly, Chiyou and Keiichi are discovered by two members of the Souma family, and almost immediately discover their secret!

The Arakawa siblings are offered a place to live, as long as Chiyou can keep the secret. But the problem widens when one of Chiyou's three best friends, Fukuyama Youko, leaves her aunt's house to find a new place to live and discovers the Souma secret as well!