Chishiki to Keiken

A young man named Keita finds himself in a complicated situation when his older sister's friend, a woman named Yuki, moves into his apartment. Yuki is experienced and confident, while Keita is shy and inexperienced. As they begin living together, Yuki takes an interest in Keita and decides to teach him about intimacy and relationships. Their interactions blur the lines between friendship and something more, leading to a series of intimate encounters that challenge Keita's understanding of love and desire.