Hawaii Five-0 will throw out a McRollins curve ball during the season 6 premiere.

'Hawaii Five-0' Season 6: Pirates & Buried Treasure; Premiere Plot Revealed

The Sept. 25 episode will have a little something for everyone - the adventure of a pirate treasure hunt, the romance of Kono (Grace Park) & Adam's (Ian Anthony Dale) wedding reception, and the mystery of McGarrett (Alex O'Loughlin) and Catherine's (Michelle Borth) future.

Despite the packed slate, showrunner Peter Lenkov promises that each storyline will get its due.

'Hawaii Five-0' Season 6: Willie Garson To Return, What Will His Art Thief Be Up To?

"We never just deliver plot," Lenkov told Entertainment Weekly. "There's plenty of character stuff in the first episode in season 6, including a huge turn in the McGarrett/Catherine relationship."

Catherine was MIA in the Middle East for all but one episode of season 5, and her sudden return left McGarrett a little off kilter. The duo managed to avoid addressing the future during the season 5 finale - disposing of a nuke provides an excellent deterrent for uncomfortable conversations - and hopefully this "huge turn" will come as the couple hashes out their hopes for the future.

"Clearly, it's a happy reunion, but it's a little awkward, also, based on how it was all left. They both have a lot to talk about, which they don't really get to in the finale, so I'm hoping that we resolve it at the beginning of next year and decide the fate of Catherine at that time," Lenkov explained to The Hollywood Reporter.

Find out more when Hawaii Five-0 returns to CBS Fridays this fall. Click the video below to see a clip of McRollins.

Tags: Hawaii Five-O television CBS