Parker's Tragic Tease In NCIS' Season 21 Finale May Explain A Lot

Contains spoilers for "NCIS" Season 21, Episode 10 — "Reef Madness"

"NCIS" Season 21 ends with the kind of thrilling finale fans of the show no doubt know they'll be getting now. Alden Parker (Gary Cole) and Jessica Knight (Katrina Law) spend much of the episode trapped aboard the USS Goddell, an old ship that's about to become a part of an artificial reef. Featuring an injured, boat-hating Parker suffering from hallucinations, the episode's title, "Reef Madness," is extremely appropriate. Incidentally, the aforementioned hallucinations might just reveal a fair bit of information about the Major Case Response Team's current Supervisory Special Agent — and precisely why he dislikes boats so much.

As Parker's blood loss worsens, he sees a little girl she calls Lily (Kensie Mills) running around the engine room. Lily soon returns in another hallucination where she's playing on a ship with a younger version of Parker (Milo Cragnotti), with his mother (Mackenzie Firgens) also stopping by to disapprove of the children's horseplay. The clear implication is that the ethereal Lily is Parker's sister, and the vibe of the hallucinations seems to strongly suggest that she's passed away under circumstances that involved both boats and Parker in some grim way.

"NCIS" Season 22 will no doubt elaborate on this aspect of Alden Parker's history, especially since the situation clearly troubles him enough for him to keep repeating Lily's name at the hospital. While he's clearly not ready to discuss the matter with his teammates, "NCIS" has a habit of unearthing its characters' dark secrets before much time passes.

Based on Parker's memories of playing with Lily on a boat and his mother's ominous warnings, it seems likely that the young girl died while the two were playing, and Parker shouldered the blame in one way or another. This would certainly account for his deep dislike of boats, which he officially attributes to his father's influence but may actually stem from the traumatic experience of witnessing his sister die aboard one.

"NCIS" fans think Parker taking over has been a good development because he brings new things into the mix, and they're also buzzing over Parker's darker side on the rare occasion the Supervisory Special Agent drops his jovial attitude and gets real. Combine the possibility of further exploring his Lily storyline with Director Vance's (Rocky Carroll) offer to Knight in the Season 21 finale, and it's clear that "NCIS" is heading into Season 22 with a nice little surplus of cliffhangers.