Late at night, alone in his apartment a young man hears the tapping on glass.

How, he thinks, could someone be at the window, when he lives on the eleventh floor?

How could that tapping, soft and deliberate, still be coming late at night and how could his dog simply disappear, from a room in which the doors and windows were all securely locked?

Tapping on glass is a tale of horror, urban myths, twice-told tales, and the awful truths that often lurk, not so far behind them.