Sibling Forbidden Desires Secret Nightly Ravishing Sessions Unspoken

Akira struggles with his feelings after Yui confesses she lied about being confessed to, yet acts as though nothing happened. One night, he discovers her taking sleeping pills, claiming they ensure deep rest. Overcome with desire, he gives in while she sleeps, repeating the act each time she takes the pills, all while maintaining the facade of a normal sibling relationship come morning.