The following contains spoilers for NCIS Season 21, Episode 4, "Left Unsaid," which debuted Monday, March 4 on CBS.

Equal parts action, drama, crime and comedy, NCIS can still command an audience after more than two decades. The series has shown no signs of slowing down. Season 21, Episode 4, "Left Unsaid" offers one of the most complicated, rapid-fire, yet satisfying and subversive storylines to date. Directed by NCIS: Los Angeles star Daniela Ruah, “Left Unsaid,” involves a dramatic missing person case when a wedding proposal goes wrong.

When a Petty Officer goes missing in Shenandoah National Park before he can finish proposing, his blindfolded would-be fianceé is less than impressed. But the prospective groom’s disappearance is worse than just a case of cold feet. NCIS finds the abandoned $20,000 engagement ring, and that's just the beginning of an almost over-stuffed episode.

NCIS Season 21, Episode 4 Crams in Plot Points

A missing petty officer, a rogue billionaire, a dominatrix running a very suspect business and the missing plans to a submarine -- all of these are key ingredients in "Left Unsaid." Some of these leads go nowhere, while others have some impressive traction. The result is one of the most interesting -- and unfocused -- plots in NCIS's past. The episode bundles everything into the classic contemporary crime drama format as the missing person case expands to include a number of offshoots, including the patent of a foreign submarine, inexplicable sources of wealth and the victim's apparent refusal to commit.

The guest stars -- Jake Thomas as missing Petty Officer Derek Bailey, Carson Fagerbakke portraying Derek's concerned girlfriend Tanya, Carly Hughes as the dominatrix dedicated to her business and Alastair Duncan playing sleazy billionaire Ron Davenport -- take recognizable archetypes and then subvert them, adding to the episode's depth. Characters set up as sympathetic take an antagonistic twist, and slimy potential villains are given humanizing traits. This has the side effect of making the plot that much more complicated to figure out.

The episode is filled to the brim with red herrings and false leads. It also makes liberal use of fake-outs, each one more hilarious or disturbing than the next. Some of the twists verge on soap opera levels of drama and intrigue. This isn’t necessarily a bad thing, considering NCIS is a long-standing example of successful drama. However, given the fast pace required to get everything into the episode, moments that would be emotional and gripping have considerably less impact than they should. There are scenes -- mostly involving Duncan's surprisingly vulnerable depiction of Davenport -- that are surprisingly tender, but the softness is quickly glossed over in favor of moving forward as quickly as possible. NCIS has a mystery to set up and unravel, and does so competently. Even with all the false turns, writer Yasemin Yilmaz leaves enough bread crumbs for more seasoned viewers or mystery genre lovers to feel satisfied.

'Left Unsaid' Keeps NCIS' Balance Between Crime and Comedy

One of the chief draws of NCIS is the rapport between the main cast, and the subtle laughs they share as they unravel murder and mayhem. The comedy in "Left Unsaid" comes by way of dry, witty dialogue, Nick Torres's mold problem, Torres and Alden Parker's roommate situation, and the struggle to maintain a healthy diet. Plus, there's a BDSM safe space at the center of the crime and hijinks ensue within. (Apparently “gnomeophobia” is a real thing. Who knew?)

Most of the laughs come from Wilmer Valderrama's Torres -- whether it's Torres' ill-fated diet or Kasie Hines obsessing over the mold in Torres' apartment with an inappropriate amount of glee. It's just fun to see Director Leon Vance, Jessica Knight and Timothy McGee (played by Rocky Carroll, Katrina Law and Sean Murray respectively) tease and torment Torres with forbidden fries, slimy green smoothies, gripes about grapefruit and just more work in general -- the sort of Friends-level repartee and ease that this group is so famous for. There are moments when this comic relief disrupts the flow of the episode, causing a couple of tonal stumbles. However, for the majority of the hour, humor and suspense are nicely balanced. Nowhere is this more apparent than in the scenes within in the Bold Ventures safe space, with Valderrama and Gary Cole delivering straight-faced witty dialogue.

NCIS Season 21, Episode 4 Has a Complicated Story, but Simplified Visuals

While there's a lot going on in "Left Unsaid" plot and performance-wise, the same can't be said for its technical elements. The episode is usual, respectable and standardized NCIS fare. The lighting is soft and decent in the scenic sequences in Shenandoah River Park. However, in other settings, the color is somewhat drained and almost monochromatic. Not helping are the nondescript art direction and costume design. It’s unfortunate, given that some of the locations -- the aforementioned Shenandoah River, a sumptuous mansion, the ever-faithful NCIS office -- are quite lovely.

But the biggest technical drawback is the episode's camera work and cinematography. While some sequences some beautiful, panoramic settings, the camera is notably shaky, unsteady and at times distracting, especially in closer shots and intimate scenes. “Left Unsaid” is a solid episode with a surprising amount of tenderness, mostly because it gives NCIS more turns than a game of chutes and ladders. While its brevity cuts some of its stronger elements short and its technical flaws hold it back in places, it’s still a worthy watch.

NCIS airs Mondays at 8:00 p.m. on CBS.