The final episode of the series, "Watson," delivered another major twist in the series' storyline regarding Sherlock Holmes, who seemingly returned from the dead only to be a symptom of Dr. John Watson's glioblastoma. The episode of "Wathenight," which was canceled after two seasons, revealed that Holmes was actually a result of Watson's brain tumor. The series finale of "The Cobalt Fissure," featuring Eddie Izzard as "Sebastian," will be aired on Sunday, May 3.