When a man is murdered in the woods and the main suspect appears to be a giant ape, Hannah steps in to solve the mystery. Does Bigfoot really exist? Hannah is delighted to reconnect with her former roommate, Susan Lockley, owner of Scarborough Fairs, at a college reunion, and agrees to step in when Susan's assistant drops out of managing the Sasquatch Sesquicentennial in Granite Falls, Oregon. But when Martin Radcliffe, a professional debunker, is found murdered, surrounded by gigantic footprints, the culprit appears, or was meant to appear, obvious: Bigfoot.
Fantasy or fact? As the conference disintegrates into a chaos of finger pointing, mistrust and fear, it falls to Hannah to restore order. Working closely with Jake, a retired policeman and his K-9, Harley, Hannah hastens to stave off the vigilantes and solve the crime before Bigfoot, if he exists, comes one step closer to extinction.