Detective Sherlock Holmes, along with his sober companion, Dr. Joan Watson, uses his uncanny ability to read people and analyze crimes to assist the NYPD on some of their more difficult cases. In the season premiere, Holmes consults on a home invasion that resulted in murder.

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 tries to determine who has been killing weak and terminal patients at a hospital, making it look like they died of natural causes. Meanwhile, Sherlock learns more about Joan’s decision to walk away from her surgical career.

Joan is invited to dinner with Sherlock's father. Meanwhile, Sherlock investigates the crash of a small jet, unraveling a mystery beyond a simple accident.

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.

While investigating an explosion that kills two people, Sherlock discovers a crime that’s been lying dormant for years. Meanwhile, Watson encourages Sherlock to finally pick a sponsor.

Sherlock uses his trademark deductive reasoning skills to find the killer of a college professor. Meanwhile, Watson gets a call from a former lover who needs her help in disproving hit-and-run charges.

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 and Joan investigate the murder of the general manager of a high-end Manhattan hotel whose body is found inside an industrial laundry machine. Meanwhile, since Joan’s time with Sherlock is almost up, he offers her an apprenticeship.

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 pursues Martin Ennis, an unpredictable criminal, before he strikes again. During the investigation, Sherlock is forced to work alongside Kathryn Drummond, the FBI profiler who literally wrote the book on Ennis. Meanwhile, Watson faces eviction from her apartment.

When Sherlock's ex-drug dealer, Rhys, comes around for help, Watson is concerned about Sherlock's sobriety after Rhys implies that Sherlock on drugs made a better detective.

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 investigates a case involving a wealthy philanthropist who believes his incurable illness was given to him on purpose. Meanwhile, Sherlock tries to teach Joan his deductive skills by sending her to a suspicious dry cleaning establishment.

Joan investigates her first solo case when a wife disappears. The missing woman left behind a tear-filled video that mentions a murder on a subway platform. While Joan searches for the vanished lady, Sherlock probes the murder.

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.

Sherlock and Joan hunt for the accomplice of a murdered blackmailer who targeted families of rape victims. Meanwhile, Sherlock resists celebrating his first year of sobriety.

Sherlock resumes his hunt for Moriarty when Sebastian Moran reveals that a man who was thought to be dead from a heart attack was actually on the list of intended victims from Moriarty.

Sherlock agrees to take a case from a man claiming to be Moriarty, hoping it will bring him closer to finding his nemesis. Meanwhile, Gregson encourages Joan to give up the dangerous line of work she has chosen and go back to being a sober companion.

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.

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.

Sherlock is called to London to revisit an old case, where he is forced to face his older brother, Mycroft. Although the siblings suffered a drastic falling-out a few years earlier, Mycroft allows Sherlock and Joan to stay in his new home, 221B Baker Street. With Joan in the middle, the brothers are forced to confront their very complicated history.

When a well-respected mathematician is found dead, Holmes and Watson set out to solve a murder and the purpose of the highly guarded equation he was trying to decipher. Meanwhile, Watson is conflicted when the son of a former patient approaches her for a loan.

When Holmes and Watson set out to track down a civil contractor who leaked classified information, their lives are disrupted when they are targeted by the group of cyber-activists protecting him. Meanwhile, Joan takes the advice of a friend and signs up for an online dating service.

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 Captain Gregson’s home is invaded, Holmes and Watson work to find the masked gunman before he strikes again. Meanwhile, Gregson gives his team some insight into his private life.

Sherlock’s brother, Mycroft, arrives in New York and enlists Holmes and Watson to help solve a case involving his former fiancée. Meanwhile, Sherlock has a difficult time accepting Mycroft and Joan’s relationship.

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.

Holmes and Watson uncover the identity of a serial killer whose case has gone cold and find themselves butting heads with the NYPD.

When an investigation goes horribly wrong, Sherlock must testify in an official police inquiry which jeopardizes his and Watson’s future with the NYPD

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.

Holmes and Watson come face to face with Moriarty when their one-time adversary is brought in as a consultant on a kidnapping case. Meanwhile, Detective Bell continues his struggle on the road to recovery.

When a body is found in a barrel, Holmes and Watson launch an investigation into the mafia’s ties to the murder. Meanwhile, Sherlock attempts to make amends with Detective Bell.

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’ latest investigation takes him inside a professional dance company when an up-and-coming ballerina is murdered. Meanwhile, Watson embarks on a solo enquiry to find a homeless veteran when his friend alleges he was abducted.

Tensions rise when Holmes and Watson are forced to partner with Gareth Lestrade, Sherlock’s former Scotland Yard colleague, on a bombing investigation.

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.

When a famous cancer researcher is found dead, Holmes and Watson must determine if the scientist’s untimely demise was tied to his latest cutting-edge invention. Meanwhile, Bell is finally cleared to re-enter the field.

A serial killer known for biting his victims appears to be killing again, even though he was presumed dead.

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

When Sherlock’s brother Mycroft makes a surprise return to New York, his motivations cause discord between Sherlock and Joan. Meanwhile, a missing person case takes Sherlock and Joan inside the world of unmanned aeronautics.

Business becomes personal for Sherlock when he is forced to partner with his estranged brother, Mycroft, to solve a case with life-or-death consequences.

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.

Rising tension between Sherlock and Joan brings their partnership to a crossroads, but they endeavor to put their differences aside while they help Sherlock's brother, Mycroft, who faces accusations of treason and murder.