Joan discovers a murder in Phoenix that Reichenbach may have ordered. Sherlock tells her to forget Reichenbach and to leave it to the NSA. A sculptor, Caroline Gibbs, is murdered. Sherlock hasn't taken Joan's lead to NSA Agent McNally. A serial killer named The Ghost of Brooklyn who had struck a decade earlier is suspected in Gibbs' death because his DNA was found at the scene. The Ghost is captured. He is Albert Wu, a man who accidentally contaminated DNA swabs at the manufacturing plant where he worked. So The Ghost doesn't actually exist. The Ghost murder cases get sent back to the police for further investigation. Benjamin Long got into an argument with Caroline over her noisy dogs. Long says strange men were visiting Caroline at all hours and thinks she's a drug dealer. A dog had bit Caroline's killer so Marcus and Sherlock check on dog-bite victims. One of them, Zachary Fowler, stole cell phones. Sherlock admitted to Joan that McNally had threatened everyone Sherlock loved. Diana Long was having an affair with Caroline. Diana said the killer took Caroline's German Shepherd, Ollie. Sherlock and Joan decide that the killer wasn't after Caroline but was after  Ollie,  who was a marijuana-sniffing police dog. Sherlock has SAS agents looking into Reichenbach's operation. The trio interrogates Enrique Ruiz, leader of a local drug cartel and he denies he has after to do with the murder or the dognapping. Joan snapped a photo of Ruiz's marijuana-shipping schedule. Ollie is found at a railroad. A shipment of Ruiz's marijuana is stolen from a train car, which may have been why Ollie was taken. Fowler, the brother of Ruiz's lawyer, is the culprit. Ollie tracks down the pot in Fowler's garage. Reichenbach is aware of Joan's investigation of the Phoenix murder.