My little sister comes to Tokyo from our hometown to see me. "It's been a while, big brother. I missed you." When I reunite with Ruri, who has grown into a beautiful girl who looks good in her uniform, I remember the forbidden relationship we had when we still lived together as a family. As soon as we arrived at my room, brother and sister become man and woman, and they repeatedly engage in passionate, passionate, and lewd sexual acts that are filled with love. "I love you, big brother! Cum inside me!"