Stephen Fry returns as Dr. Gordon Wyatt. Booth, still suffering some lingering effects from his brain surgery, has to get re-certified for FBI marksmanship, but is not the accurate shot he was before going under the knife. He and Brennan investigate the death of a little person who was a former wrestling star.

When human remains are discovered in the belly of a shark, Brennan and Booth are brought in to identify the missing person. Evidence suggesting the victim had been the prey of several fish directs the team’s investigation to The Aquarium of the Atlantic, where a guest lecturer and notorious self-help guru preaching the healing power of the ocean has gone missing. Meanwhile, both Brennan and Booth navigate their own relationship when a marine biologist shows interest in Booth.

The city anxiously anticipates the arrival of Heather Taffet, more notoriously known as "The Gravedigger," for her final appeal after being sentenced to death for a kidnap-murder and a series of similar coldblooded crimes. But when a bullet targeted at The Gravedigger is fired from a distance and hits her, the Jeffersonian team is tasked to piece together the sniper's precise location as well as identify the suspect and his motives. With the help of probing investigator Caroline Julian, Booth and Brennan put together a list of likely suspects, but the evidence and the remarkable skill needed to pull off the crime leads the team to believe that the crime was an inside, professional job, leaving Brennan's father Max and even Booth as plausible suspects. Meanwhile, Sweets attempts to put on a brave face after being caught in the firestorm just moments following a chilly encounter with The Gravedigger.

A body disguised as a scarecrow is found with a bullet wound in a remote cornfield, and the team is forced to work against the clock to avoid a storm and potential complications that would affect the evidence. Booth and Brennan interrogate the victim's three wives, who are also sisters, and learn that jealousy between the sisters and their desire for their husband's attention had caused a major rift in the family. Booth and Brennan also question one relative who disapproved of the victim's polygamy. Meanwhile, Cam loses confidence in her relationship with her on-call doctor boyfriend, but they both realize they need to make their relationship a priority.