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.

The episode was rated 7.90 from 1862 votes.

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.

The episode was rated 7.93 from 1734 votes.

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.

The episode was rated 7.93 from 1771 votes.

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.

The episode was rated 7.93 from 1805 votes.

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.

The episode was rated 7.94 from 1913 votes.

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.

The episode was rated 7.96 from 2095 votes.

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.

The episode was rated 7.97 from 1834 votes.

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.

The episode was rated 7.98 from 1763 votes.

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

The episode was rated 8.03 from 1924 votes.

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.

The episode was rated 8.06 from 1839 votes.

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.

The episode was rated 8.18 from 1961 votes.

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.

The episode was rated 8.25 from 1864 votes.

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.

The episode was rated 8.26 from 1966 votes.

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. Sherlock and Joan once again find themselves in the crosshairs of the enigmatic Moriarty.

The episode was rated 8.44 from 1943 votes.

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. Sherlock and Joan once again find themselves in the crosshairs of the enigmatic Moriarty.

The episode was rated 8.46 from 1180 votes.