Holmes and Watson face their greatest challenge to date when a murder investigation threatens to destroy their partnership.

Holmes and Watson's deadly conflict with Sherlock's former friend Michael intensifies when their newest victim looks to be the serial killer's latest prey.

Holmes and Watson race to locate a missing woman when Harlan Emple, Holmes' friend and "Irregulars" mathematics expert, becomes the prime suspect in her disappearance.

Holmes and Watson search for a killer choosing victims based on the predictions of a deceased man who claimed to foresee the future deaths of others, including the murder of Sherlock Holmes.

Holmes and Watson investigate multiple motives for murder when a zoologist is killed because of his numerous love affairs or his trailblazing research. Also, Holmes finds himself the victim of identity theft after his medical records are stolen.

Holmes and Watson discover that the murder of a robotics engineer may be connected to his groundbreaking secret research in the area of real-life teleportation. Also, when Detective Bell is shut out of a required class he needs in order to complete his master's degree and join the U.S. Marshal Service, he is shocked to discover the course instructor has personal reasons for denying him access.

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 race to help Detective Bell when he becomes a victim of a bio-terrorism attack at the precinct and the station is quarantined. During the lockdown, Captain Gregson and Detective Bell begin to suspect they are trapped inside with the perpetrator. Also, Watson faces the difficult task of helping her mother, Mary, accept that her advancing Alzheimer's disease requires her to receive more medical care.

Holmes and Watson investigate the poisoning of a relocation expert and discover the man led a decades-long secret career as a contract killer before his death. Also, Watson's path to adopting a child suffers a setback as she prepares for a home visit from her agency case worker.

Detective Bell considers leaving the NYPD when he is recommended for a once-in-a-lifetime career opportunity. Also, Holmes and Watson are hired by a private client to investigate the disappearance of a young woman who led a double life online as a financial dominatrix.

Holmes engages an old foe to protect his father after he learns Morland is in danger of being killed. Also, Holmes and Watson search for a killer connected to the tobacco industry when a lawyer who was in the process of reviewing a major cigarette distributor's finances is murdered.

Sherlock and his father, Morland Holmes, attempt to repair their strained relationship upon learning of a death within their family. Also, Holmes and Watson discover a link between their latest case and the world of Egyptian antiquities when they search for a killer who tried to mummify his victim.

Holmes' former sobriety sponsor, Alfredo, asks for his help with an illegal endeavor in order to save his brother. Also, Holmes and Watson investigate the poisoning of a biology professor who was working on a secret genetics project prior to being killed.

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 find themselves on the hunt for a serial killer after a murder rocks their inner circle. Also, Holmes' neurological recovery regresses and his sobriety wavers as his commitment to catching the killer grows into an obsession.

Holmes and Watson enter the world of nuclear security when they investigate the murder of an ex-Yakuza gang member. Also, Captain Gregson is blindsided by a stunning personal confession from his daughter, Hanna, a police sergeant.

Holmes and Watson retrace Holmes' steps after he finds himself in possession of a severed head and no memory of the past six hours or why he has it.

Watson considers making a major life change after reading her own therapy file while Holmes and she investigate the murder of her former psychologist.

Holmes and Watson enter the world of rare antiquities when they investigate a case in which victim was killed during a Revolutionary War reenactment. Also, as Holmes grows frustrated with the length of his cognitive recovery, he finds solace in his growing friendship with Michael.

Watson and her half sister, Lin, have conflicting reactions when their estranged biological father dies. Also, Holmes and Watson find themselves on the hunt for a stolen plutonium shipment they fear will be used to make a dirty bomb after a Department of Energy inspector is killed with a lightning gun.

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.