Booth goes missing six months after he and Brennan left their careers behind, but a case with ties to the couple pulls Brennan back into the world of forensic analysis, which brings her into contact with a member of Booth's family and Arastoo Vaziri, who's taken the lead at the Jeffersonian in her absence. Meanwhile, the FBI investigate Booth's disappearance, but one agent's tactics are bad for the team's morale.

On Brennan and Booth’s first official day back at their respective positions at the Jeffersonian and the FBI, things get exciting when remains are found at a fish farm under suspicious conditions, prompting them to investigate. After it’s discovered that someone harvested several of the victim’s internal organs before he was dumped in the water, Angela tracks down the seller and buyer of the organs to try to uncover important details in the case. Meanwhile, Booth readjusts to his position back at the FBI and discovers Aubrey has taken over his old office; Hodgins pushes Angela to showcase her photography work; and Cam struggles with her decision to choose work over her relationship with Arastoo.

It’s Halloween time at The Jeffersonian as the team gets a surprise visit from Lt. Abbie Mills and Ichabod Crane, who have traveled from the spooky town of Sleepy Hollow to help on a murder case of a young woman whose body is found on top of a 18th century military general’s headless body. The new foursome must figure out how to work together to discover who the 200-year-old headless corpse is and how the two murders are linked. Meanwhile, Booth and Brennan come up with the ultimate Halloween pranks to play on each other.

The crossover continues on Sleepy Hollow S03E05 Dead Men Tell No Tales (II).

The team investigates the murder of an escape artist whose body is found in the woods. They discover that the victim worked at the Magic Palace, and had some secret activities in the works that might have made him enemies in the magic community. Meanwhile, Brennan and Booth poll their friends as to whether or not the tooth fairy should visit Christine, and Angela continues to work with Sebastian Kohl on her photography.

Booth and Brennan go under cover at an Old West-style shooting competition; Angela and Hodgins talk about the future; Cam and Sebastian grow closer.

Hodgins is eight weeks into his rehabilitation for his paralysis and forced to navigate life in a wheelchair. Meanwhile, Brennan and Booth investigate the death of a public defender who had multiple defendants from previous cases with motives to kill her.

The Jeffersonian investigates the decomposing body of a social worker in the park, but evidence suggests the killer lived with the body for months before dumping it. Things get even more complicated when they determine another set of remains has similar details, which link the victims to a serial murderer who had sinister interactions with his victims' bodies. Booth and Aubrey consult with behavioral analyst Karen Delfs to help with clues to the killer's identity, while Cam tries to determine what (and who) she wants in her romantic life.

The team investigates the body of a private investigator who was found frozen in ice, after being dumped in the Potomac. The victim, a man with many enemies, was a "fixer" who made sure his clients' problems got "resolved." Meanwhile, Aubrey is shocked to find information tied to his father's whereabouts, Angela and Hodgins continue to work on their rocky relationship, Brennan and Booth get Christine's first report card and criminal behaviorist Karen Delfs asks Aubrey out on a date.

A drunk college student discovers the dead body of a Secret Service agent just before a presidential visit to the area. Booth is ready to hit the ground running and turns to Secret Service agent and former colleague Brandt Walker for information, but is surprised to learn the Secret Service has reservations about Booth’s involvement in the case. The team uncovers some shocking evidence that heightens the seriousness of the case, causing Booth to step up for his country. Meanwhile, Brennan is out sick with the flu and former intern Dr. Colin Fisher returns to the Jeffersonian to run lead on the case, but Brennan refuses to be kept out of the loop. Also, Hodgins takes his life into his own hands and turns a corner after a potentially dangerous experiment.

The team investigates the death of a popular professional hockey player whose headless corpse was dumped in the river. As Booth and Aubrey question the player's coach, Booth's depth of hockey knowledge is integral to solving the case, and he's reunited with a hockey rival from his past, putting him back on the ice once again to face off against him. Meanwhile, Hodgins and Oliver have a competition of their own when Hodgins builds two drones and they compete to retrieve the victim's missing head, and Booth and Brennan attempt to declutter their home.

The team investigates a body found at a glass recycling plant with a diamond lodged in its jaw. French Inspector Rousseau approaches the team with an accusation against the Marquis De Chaussin, who is revealed to be the victim's husband and lives in Virginia. Meanwhile, Booth discovers he suffers from a temporary eye illness, and Hodgins thinks he's being followed by a ghost.