Season 2 ends with the relationship between Holmes and Watson coming to a crossroads, but they agree to put their differences aside to help Sherlock's brother Mycroft, who faces accusations of treason and murder.moreless
As Holmes and Watson work a standard murder investigation, they encounter MI-6 and find the case has international and political inferences. Watson re-examines her relationships with Mycroft and Sherlock.
A surprise visit from Sherlock's brother Mycroft leads to discord between Holmes and Watson. Meanwhile, Sherlock and Joan investigate a missing person's case that takes them into the world of unmanned aeronautics.
Holmes and Watson chase the source of a lethal toxin after a pickpocket dies of anthrax poisoning.
Holmes and Watson investigate when a presumed dead serial killer looks as if he's killing again.
Holmes and Watson investigate when an influential cancer researcher is murdered. They must figure out if his new cutting-edge invention played any part in his death. Detective Bell is given clearance to resume field work.moreless
Holmes and Watson are called in to consult when a woman, who was thought murdered by her husband years ago, appears now to be a victim of a kidnapping after her husband receives a ransom demand. Holmes and Watson are eager for Lestrade to leave the brownstone but he doesn't seem inclined to do so.moreless
Tensions rise when Sherlock and Watson are teamed up with Lestrade to find the person responsible for a bombing.
When a up-and-coming ballerina is murdered, Sherlock is called in to solve the case. Watson tries to find a homeless veteran after his friend reports him as kidnapped.
As Watson peruses one of Holme's cold cases, she figures out that a rare prehistoric fossil is tied to the unsolved murder. Sherlock is in uncharted territories as concerns his duties as a sobriety sponsor.moreless
While Holmes tries to make amends with Detective Bell, he and Watson look into the mafia's association with a body found in a barrel.
Moriarty is brought in to consult on a kidnapping case, bringing Holmes and Watson face to face with their former adversary. Detective Bell persists in his efforts to make a full recovery.
Holmes and Watson set out to determine which client killed a hedge fund manager running a Ponzi scheme. Sherlock considers becoming a sponsor for a recovering addict.
An official police inquiry into one of Sherlock's investigations puts his and Watson's future with the NYPD on the line.
It's the NYPD versus Holmes and Watson when the two sleuths uncover a cold case serial killer.
The murder of beautiful woman, linked to a billionaire CEO, catches the attention of Holmes and Watson. Mycroft does his best to convince Sherlock to move back to London.
Mycroft shows up in New York to ask Holmes and Watson to solve a case concerning his former fiancée. Mycroft and Joan's relationship is a source of contention with Sherlock.
Homes and Watson get a look into Captain Gregson's private life when they investigate after masked men invade the Captain's home.
When Holmes and Watson discover an assassin's body, they must delve through the mob world for an answer. Watson helps a friend find the man of her dreams.
As Holmes and Watson investigate the murder of a financial consulting company's CEO, a mysterious woman from Holmes' past surfaces as a suspect.
Watson and Holmes search for the civil contractor responsible for leaking classified information but soon find themselves targeted by cyber activists. Joan decides to sign up at an online dating service.
Holmes and Watson investigate the murder of a well-respected mathematician and look into the guarded equation he was trying to decipher. Watson is at a loss when a former patient's son asks her for a loan.moreless
Holmes and Watson head to London for an unsolved mystery investigation and to look up his former mentor, Gareth Lestrade. Sherlock joins up with his estranged brother, Mycroft, who discloses some secrets.
When Piper Chapman is forced to swap her privileged lifestyle as a public relations executive for 12 months in a minimum-security prison, she quickly finds it is easy to make enemies.
Flashbacks reveal what led to Sherlock's downfall into addiction as the re-emergence of Irene Adler leaves Sherlock stunned.
Once again the mysterious Moriarty has his sights set on Holmes and Watson.
A man claiming to be Moriarty hires Holmes to solve a murder. Watson is being pushed by Gregson to go back to being a sober companion rather than pursuit dangerous exploits with Holmes.
The hunt is on after Sebastian Moran a.k.a. M reveals to Sherlock that a man dead from an apparent heart attack was actually a victim of Moriarty.
Holmes and Watson look for a murdered blackmailer's accomplice. The blackmailer was targeting families of rape victims. Sherlock opposes celebrating his one year of sobriety.