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 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.

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 Watson joins forces with Holmes and Kitty to locate a missing nurse she used to work with, the woman’s trail leads them to another person who has recently disappeared.

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.

When two New York City paramedics are killed during a kidnapping, Holmes and Watson join the manhunt to find the murderer and the woman he abducted. Also, Holmes learns important information about his recovery sponsor, Alfredo, that strains their relationship.

When Sherlock finds himself distracted by his father’s ongoing presence in New York City, he offers to help Morland resolve a work issue in exchange for his prompt departure home. Also, Holmes and Watson’s investigation into the double murder of two men who looked alike leads them into the world of facial recognition technology.

When an archeologist is murdered, Holmes and Watson believe the man may have been killed for what he discovered during his last excavation in a local landfill. Also, Sherlock’s relationship with Alfredo, his friend and former sobriety sponsor, hits a rough patch.

Holmes and Watson investigate a homicide in which the victim was murdered in a manner reminiscent of the crimes of an infamous, and already incarcerated, serial killer. Also, Sherlock and Joan tutor Detective Bell for a police sergeant’s exam that would lead to a promotion and a post at another precinct.

Holmes and Watson must search for a killer without any physical evidence to aid them after a bomb is detonated in the New York City morgue. Also, Watson is suspicious when an NYPD detective she’s in a grudge match with asks her to consult on a case.

When Watson runs into Captain Gregson and his secret girlfriend, a former NYPD officer, she inadvertently sets the couple’s breakup in motion. Also, Holmes and Watson investigate the murder of a wealthy woman who left her considerable estate solely to a beloved dog.

At the urging of Morland’s wealthy associate, Henry Baskerville, Holmes and Watson look into the death of his brother and discover that a witness saw the man chased to his death by a large, glowing animal.

When Holmes and Watson are pulled into a double-homicide investigation, they discover the victims were staging a fake murder right at the moment they were killed. Also, Watson's inside man at Morland's office encounters a problem that threatens to expose her spying to Holmes and his father.

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.

Joan worries Sherlock’s sobriety is at risk when she learns he has been lying to her about attending recovery meetings. Also, Sherlock and Joan discover a man’s death caused by ingesting poisoned sausage is connected to a lab working on a breakthrough in the artificial meat industry.

Holmes and Watson investigate the murder of a man Sherlock considered one of New York’s worst private investigators. Also, as Holmes stews over being beaten by Shinwell, he decides to take out his aggression by dismantling a local organization of private investigators.

As Holmes confronts a medical diagnosis that threatens both his career and sobriety, he meets Michael, a man who credits Sherlock for helping him conquer his own addiction. Also, Holmes and Watson are hired by a reformed party girl heiress to find her missing partner in a years-old sex tape that has just leaked online.

Holmes and Watson’s search for the killer of a woman found encased in cement takes them inside the clean technology industry. Also, Watson takes a giant leap forward regarding her interest in adoption

Holmes and Watson’s investigation into the murder of a religion professor puts them on the hunt for a killer connected to the occult. Also, Holmes and Watson curate a list of potential replacements for Detective Bell when it looks likely the officer will be asked to join the U.S. Marshal Service.

Holmes and Watson try to work a stateside investigation from London when someone close to them is gravely wounded by an unknown perpetrator in the United States. However, Holmes’ stateside legal trouble – the result of a confession to a murder he didn’t commit – threatens to derail their efforts.

Tech billionaire Odin Reichenbach hires Holmes and Watson to investigate a personal threat he suspects originated from within his own company; Holmes and Watson search for a motive behind three seemingly unconnected murders.

Sherlock and Joan investigate the murder of a criminal who made his living by stealing from other criminals. When Gregson resumes leadership of the precinct, he suspects his interim replacement is responsible for one of his best detective’s suspicious departure.

Tech billionaire Odin Reichenbach inadvertently provides Holmes and Watson with a lead that could give them evidence that brings him to justice.