シャーレの当番中（四徹目）急に停電を起こし視界が悪い中誤ってケイちゃんを押し倒してしまった先生。いつものノリで領域展開「先殺私死」が発動するかと思いきや、何やらケイちゃんの様子がおかしいようです...。
総力戦「屋内戦・生徒と先生の境界線」開催です！

While on duty at Schale (on his fourth sleepless night), the power suddenly goes out. Stumbling in the dark, Sensei accidentally pushes Kei-chan down. Just as he expects Kei-chan to cast her "Kill Sensei, Then Myself" domain expansion, something about her seems off...
Total Assault - "Student and Teacher's Boundary (Indoor Warfare)" is now underway!