NCIS: Los Angeles is built around its dynamic duos.

From Sam and Callen to Kensi and Deeks and Eric and Nell back in the office, these terrific tandems make the show click. But they're about to be thrown for a loop.

Creator / executive producer Shane Brennan tells TV Line that in an early episode this fall, “circumstances will dictate” a temporary shuffling of the unit's partners.

The parties involved are not happy about it, either.

Sam partnering with Deeks? We'd pay to see that for one week.

"People are like, ‘Really? I’m with him?’” Brennan teases.

The Season 3 premiere September 20, which will play out in real time and in which “one of our favorite characters gets shot,” may factor into the partner switch-up.

Either way, buckle up, because it should be wild, even by NCIS: LA standards. According to Daniela Ruah (Kensi), it's “one of the fastest episodes I’ve ever read!”

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.