Book-smart but street-hopeless Hina is determined to get closer to her teacher, Shiro Asou. Ever since he started spending time with her outside of the classroom, Hina's been nothing but smiles. Her friends aren't so happy about the developments, and for good reason. Not only is Asou twice Hina's age, but he seems to be hiding a dark past. When strange things start happening around Hina, can she count on Asou for protection...or is being with him the greatest danger of all?