Whether it's with their slowly unraveling mysteries or character development, NCIS understands subtlety better than just about any show. "Double Identity" was a prime example.

When a former Marine goes off the grid and assumes a new life, it's up to Gibbs and the team to find out why. Our episode recap has the plot details. Now, here's TVF's review ...

Lt. John Maine, or Christian Wells as he was later known, is found shot in a National Park. He survives long enough for us to meet his two wives, Leah Maine and Rachel Wells.

It turns out Maine vanished in Afghanistan back in 2004, only to resurface in the U.S. under a different name and with a substantial, eight-figure fortune no one could account for.

Maine/Wells dies before Gibbs can do his thing, but our man does learn that back in '04, the mysterious Marine vanished during a three-person undercover mission gone haywire.

McGee (Sean Murray) and DiNozzo (Michael Weatherly) get their man.

He somehow skipped the country with five oil drums full of unmarked U.S. dollars - how he did that is a major stretch, but no matter - after the Marines took out an Afghan drug lord.

That still doesn't explain who killed him. Might it have been the wife (of the other wife, as DiNozzo naturally suspects), or one of his fellow Marines who Maine/Wells double-crossed?

Try neither.

One of his compatriots did try to track him down, but it was a P.I. who took matters into his own hands and tried to shake Maine down. A shootout followed, and you know the rest.

What was neat about this was watching the agents approach the case in their own way. DiNozzo was out to prove the wife (wives?) did it, which he always seems to think is the case.

McGee, meanwhile, did what McGee does and followed the electronic trail. Ziva put her hard core investigative skills to work, going undercover herself and one-upping the P.I.

As for Abby and Ducky?

Dr. Mallard's attire and attitude left Abby puzzled, which we loved because the men in the office barely noticed his transition to regular neckties or generally happier demeanor.

Abbs was all over it, though, speculating about Ducky's whereabouts and noticing something amiss, even if it's in a good way. Maybe it's her nose for forensics. Or female intuition.

Finally, Gibbs tracks him down in the morgue and gets him to open up about it. His mother passed away at age 98, and he already had the funeral. He's grieving by being relieved.

Maybe acting extra chipper helps mask the pain. Maybe his mother's passing was so inevitable, her suffering is finally over and a weight lifted off his shoulders. Maybe some of each.

Regardless, it was brilliantly done, with hints dropped all season long leading up to this, and his heart-to-heart with Gibbs in the morgue (and Abby at the grave) were both touching.

Terrific performance by David McCallum, who portrayed this difficult and complex subject very believably. We just hope we get to meet Sophie, the Realtor Duck's now smitten with.

Another solid NCIS installment all around. Some have commented that they aren't feeling this season, but it consistently delivers with its cases and characters virtually every week.

RANDOM THOUGHTS:

• While we enjoy Tiva speculation as much as anyone, and are intrigued by Gibbs' relationship with Hart unfolding, it was nice to have a respite from each this week.
• Mark Harmon always kills, but two scenes in particular caught our attention: Walking into the interrogation room in complete silence, and lying waiting for Ducky.
• Here's hoping for more Mortimer cameos ...

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