Sword Art Online: Mother's Rosary, Vol. 3 (manga)

Yuuki's sudden disappearance has left Asuna bereft. It had seemed like everyone was having such a good time-what did she do wrong...? She turns to Kirito in her search for answers, but she may end up wishing she'd never pulled on that thread. The most heartbreaking arc in SAO comes to a tearful conclusion...!