The Irregular at Magic High School, Vol. 16 (light novel)

Every year the Yotsuba Clan gathers it's most influential and powerful
members. And like always, Miyuki has gotten an invitation. There's only one big
difference this time: direct orders from the Yotsuba matriarch requesting her
presence on New Year's Day and a bargain that may repeal Tatsuya's status as a
pariah if Miyuki is willing to do whatever it takes...