Yūta Igarashi

The story centers on a pair of stepsiblings. When Kōta's father gets remarried, Kōta's first impression of his new stepsister Aika is that she is beautiful, but that image is shattered pretty quickly. His new stepsister is a super sassy and foul-mouthed gyaru who behaves uncontrollably while their parents are away, making Kōta's life a living hell. However, their relationship begins to change when Aika gradually warms up to Kōta's caring older-brother nature.

It had been two months since they started dating, but Yui and Naoya still weren’t used to being a couple. Just then, a man passing by called out to them. “Yui-chan?” At that moment, Yui was speechless. Standing there was the man who had been her first. Before they started dating, driven by curiosity about sex, Yui had slept with him. The man threatens to reveal her past actions to her boyfriend. And so, once again, Yui finds herself harboring a secret she can’t tell her boyfriend…