Just when we thought "Penny Dreadful" couldn't get any darker, Showtime proves us wrong with the debut of the teaser trailer for Season 3.

The Gothic thriller returns Sunday, May 1, with stars Josh Hartnett, Timothy Dalton , Eva Green, Harry Treadaway, Rory Kinnear, Reeve Carney and Billie Piper joined by Patti LuPone, returning to the series in the new role of American therapist Dr. Seward, and Wes Studi ("Hell on Wheels") as Kaetenay, a new ally of Dalton's Sir Malcolm.

The third season also introduces Shazad Latif as Dr. Henry Jekyll, Christian Camargo as zoologist Dr. Alexander Sweet, Sam Barnett as Dr. Seward's mysterious young secretary, Jessica Barden as Justin, a young acolyte to Lily (Piper) and Dorian Gray (Carney), and Perdita Weeks as Catriona Hartdegan, a scholar with expert knowledge of the supernatural.

Simon Russell Beale also returns as Dr. Ferdinand Lyle, and Sarah Greene as Hecate.