Synopsis:

Hirose Anna(23), It knows the thing that younger brother Yuuichi satisfies ones wants with its panty. Anna that gets excited by the outlet of younger brothers abnormal sexual desire comes to live as on purpose shown off. First only though it shows off, Gradually as an elder sister, I come to want to make the desire emanated firmly. And the breasts is finally used and Anna that decided to raise. Relating that started once is continuation without becoming interrupted. It escalates with the thing by which Yuuichi starts living alone...