Nobody knows the destructive power of a comet better than lunar geologist Lucy Grappelli. Now her colleague is missing and she's injured, trapped inside their crashed and dying exploration vehicle. With the commander's unheeded words of caution still ringing in her ears, arrogance may yet prove to be her downfall. The base team are working flat out, but she already knows they don't have the equipment to retrieve her at this distance. Orbiting debris from the strike has ruled out a rescue mission from Earth. Unless she can find a way to stretch her dwindling oxygen supply, and get herself the 1000 km back to the base without external help, her mission will end right here. There it is again, a movement in the shadows of the boulder field outside. Is it the slight concussion she suffered in the landslide, or is the fog of pain and loss playing tricks on her mind? She's dodged the raw power of the universe twice already, but Lucy fears her luck may be about to run out. Horror crawls across her skin, and nausea grips her by the throat. She is convinced that something is moving among those rocks; a grey something that shouldn't be out there in the vacuum on the lunar surface. And it's creeping ever closer.