Mahouka Koukou no Rettousei: Tsuioku-hen
魔法科高校の劣等生 追憶編
"Three years ago, he had the same posture. Three years ago, he had stood behind Miyuki. Yes.... Compared to three years ago, it had changed." Set 3 years prior to the present time, Tsuioku Hen tells the events that would change Miyuki's world drastically, as well as the events that led Tatsuya to become what he is now.
(Source: MangaHere)