Holmes and Watson search for a computer hacker responsible for three murders, including the death of a Russian billionaire who was visiting New York City. Also, Joan is surprised to receive a solo dinner invitation from Sherlock’s father.

Captain Gregson’s colleague from Narcotics asks Holmes to orchestrate the perfect heist inside the heavily armed and virtually impenetrable compound of a drug-dealing biker gang. Also, when Watson assists Fiona Helbron, who helped her on a recent case, she makes a surprising discovery about Holmes.

When a survivalist doctor goes missing, Holmes and Watson must determine whether he’s purposely gone off the grid or if he’s a victim of foul play. Holmes exhibits odd behavior when his romantic relationship with Fiona hits a critical point.

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.