I'll cherish this for the rest of my life

Overview

March 25th, 2095. To celebrate her 15th birthday, Miyuki Shiba goes shopping with her older brother Tatsuya in Yokohama. Miyuki enjoys her time with Tatsuya as if they are on a date, and she is ecstatic when he gives her a surprise gift. However, they are interrupted by a call from the main branch of their family, the Yotsubas, who are members of the Ten Master Clans. They ask Tatsuya to attend to an urgent matter. While Miyuki waits for Tatsuya to return, the fire alarm in the building goes off. Miyuki senses that this is a criminal act committed by someone using magic and heads toward the fire.