From Shoujo Crusade:

Azayoshi lives in an empty world, there is no hope or happiness, all she wants is a person who will never leave her side. Suddenly Ai steps into her dark world. To her he was her love. But what will happen when he discovers Azayoshi's past? Why is she keeping secrets from Ai?

Lately in this neighborhood, there have been several sightings of a suspicious man around 40 years old. Several female students are being followed. If you see a suspicious man, run away immediately. As much as possible, make sure you are not alone.