"Big brother... look at this, Azu...?"
Azuki and Kouki, siblings who grew up without the love of their parents, deepened their bond by showing each other how they masturbated. Just when they thought their relationship would continue like this, their brother told them, "I've got a girlfriend, so I want to end it."
With no emotional support, Azuki was masturbating on the bunk bed where they grew up when her brother's friend Sasaki appeared...