In the season premiere, Holmes and Watson join the NYPD manhunt for a serial bomber who is active again after going dormant for six years. During the investigation, Watson seeks help from a former criminal, Shinwell Johnson, whose life she saved when she was a surgeon. Nelsan Ellis joins the cast as Shinwell Johnson, a character who first appeared in Sir Arthur Conan Doyle's 1924 story, "The Illustrious Client."