I'll cherish this for the rest of my life

S1 E1: 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 atte...