Kawari wa Okaa-san: Futari de Orusuban

Yuuta, a young boy, is left at home alone with his mother's friend, a beautiful woman named Aya. She has been asked to look after him while his parents are away. Yuuta is shy and nervous, but Aya is kind and gentle, trying to make him feel comfortable.

As they spend time together, Aya's playful and affectionate behavior begins to blur the lines between maternal care and something more intimate. Yuuta finds himself drawn to her warmth, and the boundaries of their relationship start to shift, leading to a forbidden encounter.