hits close to home in "An Unnatural Arrangement," after a burglar breaks into the captain's home, demanding his whereabouts to his wife. It leads to digging and inspecting his old case files as they try to uncover clues as to who would want to come after him.
Botched Home Invasion
Captain Gregson's wife is rather calm under pressure, and even I learned from her reaction. The intruder waited for her to come home. Wearing a mask, he pulls out a gun on her, and she has the quick sense to hit her SUV's panic button to distract the bad guy long enough for her to run up the stairs and lock herself in the room. There, she pulls out her handgun, and when the perp is trying to break in, she shoots at the door -- no hesitation.
Unfortunately, the guy has fled the house, but did leave a few blood stains behind after getting clipped from the shots. The blood gets processed right away, as he's likely in the system if he's coming after the police captain.
When everyone gathers at the scene, it's then we find out the captain and his wife have actually separated. Is the separation in any way connected to what happened?
A Link from the Past
While searching through Gregson's files and emails, Sherlock finds in the spam folder emails from a guy who's been sending the captain fan letters that end up being intimate. The definition of a stalker.
Sherlock and Joan track him to his apartment only to hear the water running. When they make their way inside, they pass a shrine of the captain featuring mostly newspaper clippings. In the kitchen, they find the man with a gunshot wound.
All signs point to this weirdo as the culprit, but Sherlock knows he's not. He had actually shot himself, and did it in the right, which doesn't match up to the way the blood was left on the captain's wife's car.
Sure enough, the blood isn't a match. All that work for nothing. But if this isn't the guy who broke into the captain's home, then it means he's still out there.
The Assailant Strikes Again
When an ex-military man named Sam winds up dead, the security camera films the killer. They're sure it's the same guy who broke into the captain's home. What's the link between the Army man and Gregson? Nothing, he says, or nothing that he can come up with.
At the coroner's office while inspecting the body, Sherlock notices all the wounds that must have come from his job -- and then one that couldn't have because it's a stabbing wound. A visit to the mother uncovers the fact that one of the other men, Jacob, stabbed him. They were both under Monroe, James Monroe, and the light bulb goes off.
James Monroe was the man who gave a statement after the break-in at the captain's home because he had run out of his house when he heard gunshots, only to see the guy running away.
Sherlock quickly phones Gregson, who had been at his home, to go over to Monroe's house. It appears that the killer, probably Jacob, meant to go to Monroe's, but Google Maps actually led him to Gregson's! We've all had that problem at some point in our lives, probably more than once, so the mix-up is completely understandable.
Well, Gregson and the security detail who had been at his house get to Monroe's too late because he's already dead.
Finding a Reason
Jacob is brought in to the police station, but he's completely cleared, even though he clearly has the motive. For starters, he doesn't have any wounds on him, and the killer definitely would. But he does reveal that Sam and Monroe, the two dead men, were close buddies while serving. And he had stabbed Sam after finding out he was having an affair. The two men argued and he defended himself. It's hard to know how much of that story he's exaggerating, but he's innocent of these crimes.
Without any other leads to go on, Sherlock and Joan visit the woman that Sam was having an affair with, Beth. She's an archaeologist, and it turns out Sam and Monroe were part of the security detail assigned to protect the sites where she worked. Sherlock wonders if her husband would've committed the murders in a jealous rage, but Beth says that's not possible -- they were in the thick of their divorce proceedings.
Digging deeper into the link between the three, it turns out that at every excavation site, a certain bowl had been uncovered -- except for one. They believe that the three were in cahoots to steal the bowl. And sure enough, when they actually see an image of it, Sherlock remembers seeing it at Beth's house.
When they're back at Beth's, the evidence is missing! And there's no way Beth left the house with the bowl because she had been on a video conference the entire time. So it must be a partner that she's working with. The two had the Army men killed because they could've spilled what they'd done at any time.
So what happened? Beth's neighbor informs them she didn't hear anything that night, which Joan and Sherlock realize is impossible. Beth's dog barks at all the strangers. If the dog hadn't barked the night the bowl was taken out of Beth's house, then it must mean the partner is someone the dog knows and trusts -- Beth's husband.
It turns out the two made up and were partners in this archaeological crime. When Joan and Sherlock track him down to his hotel and inform him his blood would match the ones at the house, he spills everything. What's the rule for ex-spouses testifying against each other?
A Piece of Sherlock
Throughout this investigation, we see Sherlock give of himself to both Joan and Gregson. With Gregson, he tries to be there for the captain during his time of separation. He does a background check on his wife's "old friend," only to make him realize that he just needs to tell his wife she'll no longer be number two in his life to his job.
With Joan, she gets a little miffed when Sherlock solves the case that one of the other detectives specifically asks Joan to help solve. But Sherlock takes it upon himself, to "cleanse his palette" when he could've solved the other case. In the end, he ends up giving her this old trunk, one with files of all his cases that he hadn't been able to solve for Joan to take a crack at. It's such an incredible moment between the two of them, especially when Sherlock's watching her going through the trunk while she has a giddy smile on her face.