It was one of those episodes that began and ended with action, with some personal drama mixed in between.
NCIS: Los Angeles Season 11 Episode 13 was unusually topical, with the OSP tackling the scourge of black-market opioids in Los Angeles.
While Sam feared it was drugs being sold to fund terrorism, instead it turned out to be more of a turf war in the end.
It was a great start Sam and Kensi crashed a yoga class being taught by a moody instructor in pursuit of a strangely bulletproof suspect, who fell through a skylight.
They were recovering a list of undercover assets which they returned to a very pregnant FBI agent.
That would seem to have been that, except Sam was puzzled why the suspect, a former sailor, held up so well to gunfire.
That led to the introduction of Corey the Coroner, a perfectly L.A. character.
Corey told them about a black-market opioid that was in the suspect's bloodstream and that he had heard about several such overdoses recently.
Poor Corey was so eager to become a member of NCIS that he volunteered his services and handed over evidence from a John Doe who had overdosed.
Which begs the question: Why doesn't NCIS: Los Angeles have its own, in-house coroner, like the two other series in the franchise?
Probably because all three of the NCIS shows are set up a little differently, largely for variety's sake.
Also, the new has worn off.
Back in the days of CSI, every cop show had an in-house medical examiner. Now, every series needs its own computer geek.
Who knows what specialty area will be featured next? Drone pilot? Staff troll?
In any event, it's safe to say Corey won't be joining the squad anytime soon.
Like in any drug case, the two pairs had to keep getting the small fish they arrested to flip on those further up the ladder until they got closer to the bosses.
What they didn't anticipate was two separate nationalistic groups working at cross purposes.
The switched partners was a fun change of pace.
Sam and Kensi always work together well. Both are very serious about what they're doing and they get it done.
Callen drew the short straw, getting Deeks. No one feels the need to talk quite as much as Deeks (well, except Eric).
Sam and Callen have never acquired the taste for Deeks, which Kensi has. The woman is a saint, pure and simple.
While Deeks drives others crazy, one person drives him crazy -- his mother Roberta.
Bobbi made her first appearance since the wedding on NCIS: Los Angeles Season 10 Episode 17.
As to what she had been up to, it appeared that Roberta had been taking stock of her life now that her baby boy has gotten married to a woman who can take care of him.
It's always enjoyable to watch Roberta out-Marty Marty, managing to shock him with what she says every episode.
Hopefully, Kensi and Deeks helped her with her midlife crisis. But it will be more fun if they didn't.
In the big action scene, it was a hoot to have everyone go undercover to save that arrogant Dev.
Granted, Sam and Callen didn't have to work too hard to pull the identities of spectators. But Kensi was very believable as a model and the cat mask was a good look for Deeks.
It was also a great way to get Sam and Katherine together again, so Sam doesn't have to "accidentally" run into her.
Katherine's on-again, off-again assistant Lily was also a big fan of Sam's, based on that stunned look she was sporting.
Sam and Katherine are a good match. They're both mature adults and they have common interests. And neither one is needy, which is important since they both have full lives already.
Also, Katherine doesn't seem cowered by Sam's job, as she's been under fire a couple of times already. She's not in the life such as Michelle was, but she isn't shocked either, which is a plus.
The fact that she gave Sam her personal cell number and encouraged him to call means that their relationship is taking off, and soon.
Then there's Callen and Anna.
Callen knows he screwed up. He decided to be active rather than reactive and has started looking for her.
And by the looks of that final scene, he's found her, somewhere, and she's in a bit of trouble.
This promises an off-the-books mission to bring her back, probably with Hetty's assistance. This also means Arkady will appear, which is always a good thing.
However, with two encore presentations sandwiched around the Grammys Awards, followed by Super Bowl Sunday, that won't happen until at least later in February.
Finally, there was Eric, who has been back just long enough to go off the rails a bit.
Amid a potential black-market opioid epidemic, Eric was stressing about a missing mountain lion.
It's admirable to be concerned with wildlife, but as Nell pointed out, sometimes a wildcat isn't a wildcat.
Eric thrives in a precision-oriented field, so all the uncertainty in his life was knocking him for a loop. As always, Nell offered him sound advice. She's a saint as well.
To follow Sam and Callen's relationships, watch NCIS: Los Angeles online.
Do you like Sam and Katherine together?
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Dale McGarrigle is a staff writer for TV Fanatic. Follow him on Twitter.