Yuuta Asamura is still figuring out how to interact with his new stepsister, Saki Ayase.

Yuuta Asamura is still figuring out how to interact with his new stepsister, Saki Ayase.

But after finding they have more in common than expected, the two reach a comfortable equilibrium.

Things start to get out of whack, however, when Saki fails one of her exams and asks for Yuuta's help.

Then Yuuta's attractive college-age coworker, Shiori, invites him out on a date, and Saki finds a strange new emotion welling up in her heart... Just what is this feeling?