Sherlock uses his powers of deduction to consult on the murder of a young man who is shot upon entering his apartment. Meanwhile, Watson has dinner with her ex-boyfriend, Ty Morstan.

Sherlock and Watson consult on a child abduction case involving a serial killer who is nicknamed "The Balloon Man," because he leaves a signature batch of balloons at each of his crime scenes.

When Sherlock investigates what appears to be a series of murders at a top Wall Street firm, he may himself fall foul of a sociopathic slayer. Joan is set up on a blind date and shows investigative instincts.

Sherlock assists with a double homicide that has the same M.O. as a series of murders that took place 13 years ago. Meanwhile, after being frozen out by Sherlock, Watson visits his old rehab center in order to learn more about the mysterious man in her care.

Sherlock is called in to investigate when a supposedly uncrackable bank vault called “The Leviathan” is breached. Meanwhile, Joan is pleasantly surprised when Sherlock meets her family and defends her choice to become a sober companion.

Sherlock is reunited with “M.” a British criminal who appears to have followed Sherlock to New York. Meanwhile, Joan has reservations about leaving Sherlock and taking on a new client.

While on suspension from the NYPD, Sherlock investigates a suspicious hit-and-run accident involving a conspiracy theorist. Meanwhile, Watson tries to broker peace between Sherlock and Gregson.

Sherlock investigates what he believes will be an open-and-shut case after Detective Bell is attacked. However, the case takes an unexpected turn when the suspected assailant is found dead. Meanwhile, Sherlock encourages Joan to learn self-defense.

Sherlock and Joan try to prevent the largest cash vault in the U.S. from being robbed during a deadly blizzard. Meanwhile, Holmes gives shelter to Ms. Hudson, a transgender woman who is recovering from her latest breakup.

As Sherlock reels at the reappearance of his former lover, Irene Adler, a series of flashbacks unravel the tumultuous events that led to his downfall into addiction. Meanwhile, he and Joan once again find themselves in the crosshairs of the enigmatic Moriarty.

When a financial consulting company CEO is poisoned to death, a woman from Sherlock's past who emerges as a possible suspect.

Holmes and Watson find themselves digging through the dark world of the mob to find a killer when they discover the body of a former assassin. Meanwhile, Watson helps a close friend track down a mystery man who swept her off her feet.

When a beautiful young woman is murdered, Holmes and Watson investigate her ties to a billionaire CEO. Meanwhile, Mycroft makes a case for Sherlock to move back to London.

When a hedge fund manager who was also running a Ponzi scheme is murdered, Holmes and Watson must determine which of his clients is guilty. Also, Sherlock contemplates sponsoring a fellow recovering addict.

Joan discovers an unsolved murder connected to a rare prehistoric fossil when she reviews one of Sherlock's cold cases; Sherlock's responsibilities as a sobriety sponsor cross personal boundaries.

Holmes and Watson consult on a case in which a man suspected of murdering his wife years ago receives a ransom demand for her safe return. Meanwhile, Lestrade overstays his welcome at the brownstone and seems unwilling to leave.

A pickpocket dies of anthrax poisoning, putting Holmes and Watson on the trail of the toxin’s source in order to prevent more deaths.

Holmes and Watson come into contact with MI-6, the British intelligence agency, when a standard murder investigation turns out to have international and political implications. Meanwhile, in the wake of a crisis, Watson reevaluates her relationships with Sherlock and his brother, Mycroft.

When Sherlock and Joan join forces on a double homicide, Sherlock’s new apprentice threatens the investigation when she allows her jealousy of Sherlock and Joan's work rapport to override her better judgment.

Holmes and Kitty investigate the murder of a postal store owner whose death is connected to the illegal diamond trade. Meanwhile, Gregson's career is placed in jeopardy when he hits a fellow NYPD officer.

Holmes and Watson join forces with the NYPD after a police officer is murdered. Also, Sherlock searches for the creator of a “recovery blog” who is posting personal statements he has made in sobriety meetings.

Watson begins her new job as an in-house investigator for an insurance firm. However, her attention shifts to a case that is personal for both her and Holmes when they join forces to eliminate an imminent threat to Kitty.

Holmes and Watson follow a blood trail into the world of wrongful death compensation when they investigate a series of murders in which the killer leaves envelopes of cash on the victims. Also, Holmes makes a generous gesture towards Watson as she suffers through the aftermath of a personal crisis.

Holmes and Watson investigate a murder that initially looks like a road rage incident, but takes a new direction when they learn the victim was flash-frozen at the time of death. Also, when Watson’s mother finds out Joan’s brother is cheating on his wife, she puts Joan in the awkward position of confronting him about the affair.

Holmes and Watson investigate the murder of a professional skeptic, a man who debunked paranormal, religious and scientific phenomenon for a living. The case becomes urgent when his homicide reveals a potential threat to homeland security. Also, Captain Gregson’s daughter and fellow NYPD officer, Hannah, asks Watson for help with one of her cases.

Holmes and Watson look into the death of a member of Holmes’ online beekeeping community who was a researcher looking into a deadly Northeast honey bee outbreak. During the investigation, they meet Tara Parker, a brilliant entomologist, academic and the leader of New York’s beekeeping society. Also, Captain Gregson enlists Watson’s services in an off-book investigation that helps him make a life-changing decision.

Holmes learns a secret about Captain Gregson’s girlfriend when she hires him for a case she wants kept off of Gregson’s radar. Also, Holmes and Watson join the NYPD’s search for an abducted woman.

Holmes and Watson investigate a mass murder when a chef and his patrons are poisoned after dining on a tasting menu tainted with snake venom. Also, Detective Bell’s crush on a work colleague makes Holmes realize his and Fiona’s relationship is at an important crossroads.

When Shinwell comes to Holmes and Watson for help after he’s framed for a gang killing, they have three days to find the real murderer before he is arrested and sent back to jail.

When Holmes and Watson investigate a clown’s murder upstate, they discover a connection between his death and the creation of a new weaponized virus. Also, Watson helps Bell when he’s targeted by his new love interest Chantal’s ex-husband in attempt to sabotage her career at the district attorney’s office.

Holmes’ former protégé, Kitty Winter, returns to New York after a three-year absence to warn him that a killer is eliminating everyone involved with a case they worked on together in London, and they’re the next targets. As Sherlock, Kitty, Joan and the NYPD join forces to find the perpetrator, Watson discovers Kitty has a life-changing secret.

Sherlock and Joan question how well they know Shinwell when they investigate the possibility he may have gotten away with the unsolved murder of his friend, a fellow gang member. Also, Sherlock and Joan’s latest case puts them on the hunt for a treasure map rumored to lead to a fortune in pirate’s gold hidden around New York City.

When Detective Bell’s girlfriend, Chantal, is assaulted and her ex-husband is killed soon after, in what Holmes and Watson discover is a staged suicide, they search for one suspect behind the linked crimes. Also, as Bell fights the urge to seek his own brand of justice for Chantal, Sherlock makes a heartbreaking realization about the detective’s past.

Season 5 ends with Holmes and Watson pursuing an elusive criminal as a gang war erupts in New York City. While the NYPD works to contain the violence, the two investigate the murder that appears to have ignited the city-wide conflict and discover that a familiar face is pulling the strings.

Holmes and Watson enter the world of rare antiquities when they investigate a case in which victim was killed during a Revolutionary War reenactment. Also, as Holmes grows frustrated with the length of his cognitive recovery, he finds solace in his growing friendship with Michael.

Holmes and Watson enter the world of nuclear security when they investigate the murder of an ex-Yakuza gang member. Also, Captain Gregson is blindsided by a stunning personal confession from his daughter, Hannah, a police sergeant.

Holmes’ former sobriety sponsor, Alfredo, asks for his help with an illegal endeavor in order to save his brother. Also, Holmes and Watson investigate the poisoning of a biology professor who was working on a secret genetics project prior to being killed.

Holmes and Watson investigate the poisoning of a relocation expert and discover the man led a decades-long secret career as a contract killer before his death. Also, Watson’s path to adopting a child suffers a setback as she prepares for a home visit from her agency case worker.

Holmes and Watson discover that the murder of a robotics engineer may be connected to his groundbreaking secret research in the area of real-life teleportation. Also, when Detective Bell is shut out of a required class he needs in order to complete his master’s degree and join the U.S. Marshal Service, he is shocked to discover the course instructor has personal reasons for denying him access.

Holmes and Watson race to locate a missing woman when Harlan Emple, Holmes’ friend and “Irregulars” mathematics expert, becomes the prime suspect in her disappearance.

Holmes and Watson’s deadly conflict with Sherlock’s former friend Michael intensifies when their newest victim looks to be the serial killer’s latest prey.