In the middle of the battle against the rank-S cryptid Shebiti, Asuka's missing mother, Honoka, suddenly appears. At the sight of her, joy, bewilderment, and rage all battle for control on Asuka's face. Why is she here? And as something lurking deep in the shadows begins to stir, the truth of what happened on that day ten long years ago will finally come to light in the climactic series finale of Bestia!