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, 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.

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"Over the past four seasons, David has proven himself to be a tremendous leader and a great steward of our show's unique voice," Marlowe said in a statement. "I'm excited to continue our creative collaboration as he assumes his new responsibilities."The transition comes at a crucial point for the ABC procedural drama. On the Season 6 finale (watch it here

), longtime lovebirds Richard Castle (Nathan Fillion) and Kate Beckett (Stana Katic) had their wedding day ruined when Castle was run off the road by a mysterious person driving an SUV. The closing shot featured Castle's car in flames, while the whereabouts of the mystery writer were unknown.

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Prior to joining the Castle team in 2010, Amann worked on such shows as Without a TraceCrossing Jordan and The X-Files.Castle returns in the fall on Mondays at 10/9c on ABC. What do you think of the showrunner switcheroo?