It's hard to put my finger on what I liked best about Elementary Season 6 Episode 6.

Sorry. I couldn't resist.

At the center of this case of the week was a unique brand of digital storage.

Who knew there was a booming market for retired Yakuza seeking artificial fingers?

When you start with a retired Yakuza as the victim of this case, there are so many directions that things could go.

And Sherlock, Joan, and Marcus did go all over the place seeking Ando's killer.

As a former mobster, a natural murderer would be someone he had worked with in the past or something that he had done recently to step back into that life.

But, no, that would have been too obvious. Plus, good luck finding a killer within that organization.

Fortunately, an active Yakuza pointed out suspicious activity by Ando that led to other potential suspects: those who want to buy American nuclear secrets and those protecting those secrets.

That artificial finger with the built-in flash drive was a very nice touch.

The possibility of Ando selling off American nuclear secrets set off alarms bells, especially among Air Force personnel who had an unawareness of his unusual finger.

I'd never considered the idea that technological upgrades were a bad thing (except for Windows 8). I guess it makes sense that using ancient computer technology would make it harder to hack. It's kind of like old-school air gapping.

So I have to wonder why the Air Force was trying to upgrade, with a good degree of internal opposition. I suppose getting replacement parts is a bitch.

That brings us to Eddy Dundridge and his supply of legacy tech (what a frou-frou way of saying computer junk). I would never have thought those floppy discs in my basement had any lasting value.

Apparently, those discs that look so delicate actually hold up, but they don't erase well, so all the data that was once on them can be recovered. I can't believe that discs containing important U.S. currency formulas weren't torched when they outlived their usefulness. Somebody thought erasing was sufficient?

We're to believe that Col, Deakins discovered one of the currency discs, then killed Ando to halt the upgrade and took his pinky drive to create panic among her coworkers.

This very smart woman answered a call from a Yakuza member and agreed to sell the drive to him. That didn't track for me. Shinura calling out of the blue with a $5 million offer didn't seem at all suspicious? I'm guessing he likes the fantasy of a peaceful retirement someday.

It was good to have Mason in for a visit, minimal social skills and all. I want more of Sherlock's irregulars.

Another recurring character returned, under much more serious circumstances. Captain Gregson thought Hannah had her life on track, only to find out that she's an alcoholic. As if Gregson didn't have enough on his plate, now this gets thrown at him.

Fortunately, the captain has Joan, and even Sherlock, in his own way, to help him navigate this tricky passage with his daughter. It was heartwarming of Sherlock, in the doghouse with Gregson, to try to offer positive advice to him.

It will be interesting to see how much of Hannah's journey to sobriety will be included in upcoming episodes.

Unfortunately, Hannah has now met Michael, which can't be a promising development. Michael used the old fender-bender to force an introduction trick.

Hannah's roommate seemed nice. Well, that is, as long as she lasted.

The big question now is what is Michael's plan for Hannah. Since Sherlock was making negligible progress finding Michael's first victim (that we know of), did Michael figure that he needs to kill someone tangentially connecting to Sherlock to grab his attention?

I figured Michael's storyline would continue for much of the season. But, based on the previews for next episode, it seems things are accelerating on that front.

Sherlock's post-concussion syndrome was downplayed in this episode. He mentioned it two or three times in passing, but it never truly took center stage.

I'm all in favor of Sherlock's condition forcing him to work harder to utilize his natural gift. But we don't need to be hammered with it a quarter of each episode.

All in all, a twisty, turn-y episode, setting up a new phase in the Michael storyline.