Musuko no Musuko wa Dare no Mono!? ~Musuko Soudatsu Haha Imouto Sensen~

Since my father died because of a sudden sickness, my mother took care of me. It's good that she hasn't cried or felt depressed, but it's a bit frustrating when it gets to lewd things. In the middle of such a life, my sister, who lived at a girls' dormitory, was worried about us and suddenly left the dorm and came back home. My sister was stunned by our lifestyle, and thus, began to get angry. With that sort of attitude, me and mom will become useless members of society. My sister frantically tried to persuade mom and, for some reason, began planning to solve the situation by taking me away from her...? Wh...What? Things are getting a little weird...? Under one roof, the battle between the beautiful mother and daughter for me begins!