NCIS Season 21's Big Surprise Will Affect McGee In A Big Way, Says Sean Murray

Contains spoilers for "NCIS" Season 21, Episode 5 — "The Plan" 

"NCIS" might not be the first series one thinks of when it comes to huge plot twists, but Season 21 is set to pull quite the shocker on Timothy McGee (Sean Murray). In "The Plan," when his wife Delilah (Margo Harshman) talks him into taking a DNA test to facilitate her interest in genealogy, McGee is stunned to learn that he has an unknown relative. McGee doesn't want to open this particular Pandora's box in the first place, but when he does, he is shaken up, yet driven to pursue the matter.

"That freaks him out pretty good. But he goes down that rabbit hole," Sean Murray told TV Insider, admitting that he was also surprised by the plot twist. There's no word as to who McGee's possible relative might be. Still, Murray seems excited to play out the ripple effect that this might have on his character; he seems to be quite proud of his growth in general over the years and remains quite resistant to the idea of stagnation. "I remember saying early on to our writers and showrunners that McGee cannot be baby Maggie Simpson. He cannot revert to the same character every week without growing. We can't have that," he said, also noting that he and the writing team were happily on the same page.

Thus, McGee has grown and changed exponentially with time. Said exponential growth includes his relationship with another relative –  his sister, Sarah (Troian Bellisario). While audiences haven't seen Sarah in a while,  Murray admitted that he spent some time with Bellisario recently — and they both had the same question about the character's future.