While assaulting a Shuuki nest, the 7th Squad are confronted by a mysterious girl riding atop Unihorn, Kyouka s sworn enemy. Who is she, and why does she seem to recognize Yuuki? There s no time to ponder that mystery, however, as the leaders of the 6th Squad including Himari s sister arrive for joint training! The stage is set for a grudge match between the two siblings, and Himari drafts the Squad s slave-cum-caretaker to help. Not that Yuuki s complaining more masters means more sweet rewards!