MIAA-113 The most beloved sister in the S family falls into masochism after getting married... Natsuiro Miku

My sister married into a very wealthy and prestigious family. As someone who raised me like a parent, I only caused her trouble. So, I wanted her to be happy after getting married. Yet... Even though we used to communicate frequently and had a good relationship, there has been no word from her since the ceremony. Feeling concerned, I went to see my sister. The mansion was empty. When I sneaked into a room with an open door, I found a DVD. It was labeled 'Bitch Slave Pregnancy Record'... I had a bad feeling...