You wake up alone in a dark mansion. You cannot leave the place, yet something seems to lurk in the dark. Is it after you? Probably...
Fortunately, there is a light bulb still working. Only one though: you will have to take it with you on your way to the deeper parts of the mansion in order to keep away the thing in the dark. But it means walking without light from one lamp to another. Will you be fast enough? Will you discover what happened here and why you are locked in? Tread lightly on your way to the truth...