During a half-day date, Yumi decided to become sisters with Touko. On the following Monday, Yumi headed to school earlier than usual. She was determined to give the rosary to Touko today. In front of the statue of Maria, Yumi met Touko, who had arrived even earlier! The two made a promise to meet in front of the Maria statue during lunch break. After that, when Yumi headed to Sachiko's classroom, she witnessed something unbelievable...!? A memorial volume celebrating the birth of their sisterhood!