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
Dr. William Masters starts a secret study of human sexuality. We also see him run his medical practice, at a midwestern teaching hospital in St. Louis, as an OB/GYN by day while he works on his project by night. A new secretary, Virginia Johnson, shows promising relevance to his studies.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.
Flashbacks reveal what led to Sherlock's downfall into addiction as the re-emergence of Irene Adler leaves Sherlock stunned.
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.moreless
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.
With a Nor'easter as their backdrop, Sherlock and Joan attempt to keep one of the largest cash vaults in the country from being robbed. Sherlock does his best to console a transgender woman with a broken heart.moreless
Boyd and Ava try to keep their murderous secret under wraps while Raylan and the Detroit mob come to bloody blows.
Much to the frustration of the Raylan and the Sheriff's office, Drew continues to keep schtum until Ellen May is safely in custody. With Ellen May temporarily under Limehouse's protection and Boyd gunning for her, capturing her could be tricky.moreless
Boyd and the Detroit mob pull out all the stops trying to stop Drew from leaving Harlan and escaping.
Sherlock becomes intrigued by Watson's first solo case when the goodbye video left by the missing woman mentions a murder on a subway platform.
Drew Thompson and Ellen May manage to slip away from Raylan and the Detroit mob. But, with their escape route blocked they ask help of someone unexpected.
Boyd discovers that Colt has been lying about Ellen May and the identity of Drew Thompson is revealed.
No one is safe as bodies start to drop in the hunt for Drew Thompson.
A wealthy man comes to Sherlock saying his incurable illness was given to him on purpose. To teach Joan his tricks of the trade, Sherlock sends Joan to a suspicious dry cleaning establishment.moreless
Jody Adair escapes custody, leaving Raylan compelled to track him down. Boyd and Ava work their way into a high society party to fish out Drew Thompson, but find far more than they expected.moreless
When Detective Bell is attacked while off duty, Sherlock finds the case isn't so obvious as it first appeared after the suspect is found dead. Sherlock pushes Joan to learn self-defense.
When Josiah Cairn turns up missing and short a foot, Raylan teams up with Sheriff Shelby to track him down before he bleeds out. Boyd continues to hunt Drew Thompson.
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.
When the Marshals take over the Drew Peterson case, the hunt to find him accelerates for Raylan and the Detroit mobsters, leading to a sticky situation for Raylan and Boyd Crowder. Meanwhile, Colton's hunt for Ellen May starts to get desperate.moreless
While trying to predict the next move of erratic criminal Martin Ennis, Sherlock is forced to work with an FBI profiler. The same profiler who wrote an acclaimed book about the notorious criminal. Elsewhere, Watson faces eviction from her apartment.moreless