Ayame deeply admired Yui, her older brother's wife, like a real sister, and would frequently visit their home whenever she had free time. Yui was someone Ayame could confide in about anything, the one person she could turn to with secrets and troubles she couldn't share with anyone else. One day, heartbroken after a painful breakup, Ayame was comforted by Yui—and then kissed by her. From that moment on, their relationship changed completely, forging an entirely new and deeper bond between them. Ayame gradually surrendered her heart to Yui, deepening their intimate and special connection.