Martin the baby-sitter was about to fall asleep. He’d spent the last 10 minutes thinking about whether to get up and lock the apartment door. It was one of the safest neighborhoods in the city. Nothing ever happed. Still, he got up with a groan, and locked it anyway. Then he checked on the baby, and fell asleep on the couch.
That night a murderer entered the building: a giant shadow, a phantom. No one had ever seen his face. He tried the doors on the first floor. But they were locked. The same was true of the second. Then he reached the third.
As Martin slept, the door-knob to the apartment turned. But the shadow couldn’t get inside. He moved further up the building, with evil in his heart.