After the graduation ceremony... A gift from your stepmother to you now that you're an adult. Yuna Shiina

The story revolves around Yuu, who has just graduated, and his stepmother Yuna. As they spend more time together, Yuu develops romantic feelings for Yuna, which eventually leads to a forbidden relationship between them. The theme explores the complexities and tensions arising from their taboo bond, set against the backdrop of Yuu's transition into adulthood.