Lost in Shadow opens with a boy imprisoned high in a tower. A cloaked stranger enters and strikes him with an unusual weapon — not injuring him, but severing his shadow from his body and hurling it from the tower's edge.
The player takes control of this displaced shadow as it works its way up through the enormous tower, floor by floor, with one goal: reach the top and reunite with its owner. The catch is that shadows cannot interact with the physical world — only with the shadows of objects. A sylph companion named Spangle helps by occasionally shifting the angle of the light source, changing which shadows fall where and opening paths that would otherwise be impassable.