Nathan Fillion, Stana Katic and Andrew Marlowe (inset) Nathan Fillion, Stana Katic and Andrew Marlowe (inset)

Castle's first Season 7 twist is a big one.

Creator Andrew W. Marlowe will pass the showrunner torch to executive producer David Amann for the upcoming season, TVGuide.com has learned. Although Amann will be the primary showrunner, Marlowe will maintain a day-to-day presence on the show while also developing new projects as part of his overall deal with ABC Studios.

Worst ways to go: Check out the most outrageous TV deaths

Postmortem: Castle boss answers our "burning" questions about that Season 6 cliff-hanger