Ichigo Aika: Zatsu de Namaiki na Imouto to Warikirenai Ani

The plot of the hentai revolves around the relationship between a stepbrother and stepsister who is a gyaru. When the father of the main character, Kota, remarries, he meets his new stepsister, Aika. She is very beautiful and sweet, but this image quickly crumbles. His real stepsister is a very cheeky and foul-mouthed gyaru who behaves wildly while their parents are away, turning Kota's life into a living hell. However, their relationship begins to change when Aika gradually becomes imbued with Kota's care as an older brother.