We already know both The Vampire Diaries and Castle will bid goodbye to at least one important player next month.

Now, we can add Hawaii Five-O to the list of shows that will conclude its season with a major death. Says producer to Peter Lenkov to TV Guide: "There will be a murder."

Lenkov also teases that "Jean Smart [Governor Jameson], Kelly Hu [Laura Hills] and Will Yun Lee [Sang Min] are all coming back" for the May finale, with both Jameson and Hills decent candidates to be killed off because each actress has signed on for an NBC pilot.

If the spoiler of a major death isn't intriguing enough for you, Lenkov says the show's cliff-hanger will be a "Holy crap! I-can't-believe-they-did-that whodunit!"

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.