Les Eyzies-de-Tayac is known for three things: pate de fois gras, truffles, and ancient bones. This small French village is home to the largest concentration of prehistoric fossils in Europe and headquarters of the prestigious Institut de Prehistoire, which studies them. So when a local dog drags a few bones into its backyard, no one thinks twice. But when the village's chief inspector finds reason to suspect foul play he places a call to his old friend Gideon Oliver, the famed Skeleton Detective.

Once Gideon arrives, murder piles on murder, puzzle on puzzle, and electrifying surprise on surprise, in a series of unexpected events that threaten to tear the once-sober, dignified institute apart. It takes a bizarre and startling forensic breakthrough by Gideon to bring to an end a trail of deception, jealousy, frustration, and homicide almost forty millennia in the making.