Captain Gregson and Marcus didn't even have to leave the precinct to find a case.
That's because the case of the week happened right at the 11th Precinct on Elementary Season 6 Episode 14.
Events started with Gregson and Marcus closing a case, arresting a trainer in the death of a married woman he was seeing.
Well, that was quick.
Not really, since the case of the week started when the ever-observant Marcus stepped outside to call the D.A.'s office and noticed an out-of-place black duffle bag.
In the only action in the whole episode, Marcus grabbed the bag when it started to smoke and threw it into an interrogation room, shoving jackets under the doors to trap the smoke, and then isolated himself in the adjacent room.
It was such a Marcus thing to do, putting himself in danger to protect others. I was glad that a simple contamination quickly freed him from his temporary dread.
It was good to see how well the quartet worked together despite being separated under trying circumstances.
Sherlock came up with another harebrained hypothesis, presented it to Gregson, then completely ignored Gregson's order to steer clear of the cartel. Better to ask forgiveness than permission, I guess.
So Sherlock and Joan just blustered their way in to see the cartel chief, only to find out that the cartel's bombmaker had gotten killed since the first incident Sherlock had unearthed.
So after Gregson explodes about their unauthorized expedition, he wants Sherlock to figure out when the perp scoped out the precinct house.
This enabled Sherlock to use one of those perfectly geeky skills he does so well, in this case, building scale models, in order to pinpoint the date. Joan even got to run the old-timey projector thingy.
Back at the precinct house, Gregson and Marcus were working on the theory that the bomber was trapped inside the quarantine along with them.
So they did what they do best, interrogating that day's visitors, which worked well up until the time that the visitors realized that everyone was a suspect because the bomber was still in the building. Oops!
Then there was the CDC, who wasn't contributing much to the investigation. Waiting for people to keel over to narrow down the list of potential toxins seemed awfully reactive rather than proactive.
Don't they understand that procedurals depend on the scientists to blow a case wide open with some groundbreaking discovery? Having the CDC scientists just sitting and waiting seemed wrong.
Once Sherlock established the date of the scouting, it became clear that only cops were in the building that night. Joan and Sherlock even found a viable suspect, although O'Grady's motivation was somewhat murky.
But when the police computer network went down, thanks to the missing servers, all became clear.
The bomb was a hoax, and this all was a heist, aided by a CDC hazmat suit. That meant the two men "sickened" by the bomb, along with O'Grady, were in on it as unwillingly accomplices.
All in all, a pleasing little caper.
Unfortunately, the storyline about Mary's Alzheimer's worsening got the short shrift.
During the phone call Joan received at the beginning, the fears of every relative of an Alzheimer's patient was shown on her face.
While Joan frantically called around looking for Mary, she showed up to take Joan out for lunch at the restaurant that had closed years earlier.
Later on, Sherlock sagely counseled Joan that she had to be more forceful in talking with her mother about getting professional help, even if that meant trampling Mary's personal independence.
It could have been an opportunity for Joan the former doctor to dispense information about Alzheimer's, kind of a PSA within the script. But I guess having her be the hurting daughter was more important.
Also, it seemed that Mary caved a little too easily at the end.
So her going walkabout for a few hours was enough to scare her into seeking help when she returned to the full possession of her senses. More resistance would have made sense here.
Still, any attempt to work members of Joan's family into an episode is a good thing. They aren't as flamboyant as the Holmes, but they're still important to the fabric of the series.
No sign of Michael yet. The powers that be must be saving him for the last month of the season.
To follow Joan's journey, watch Elementary online.
What did you think of the case of the week? How well did Joan handle Mary's condition? Does it worry you when Sherlock is the sage one?
Dale McGarrigle is a staff writer for TV Fanatic. Follow him on Twitter.