Episode 0 happens two years prior to the TV series when the Nase siblings meet Akihito for the first time in a mission for Hiroomi. Mitsuki follows her brother on this mission and their goal is to subjugate Akihito.
Kyoukai no Kanata: Shinonome, Beyond the Boundary: Daybreak, 境界の彼方 ＃0「東雲」
