When Sherlock and Watson find the skeleton of a missing person, their investigation leads them to look at group marriages and stem cell research.

Elementary S 4 E 4 type TV Show network CBS

“All My Exes Live in Wessex” is the first episode of the season that doesn’t have some sort of plot about Sherlock’s father, Morland Holmes. It’s also the first that doesn’t in any way reckon with Sherlock’s potentially criminal actions from last season. It’s actually a welcome shift in tone, as sometimes Elementary is at its best when it strictly embraces its unique procedural elements.

The episode begins with Sherlock and Watson handcuffed to chairs in their brownstone. They’re not captives though. Instead, Sherlock has taken offense to a new brand of handcuffs that market themselves as “unpickable,” so he’s set up a test to see if he and Watson can break out of them.

When Watson’s phone goes off with a horrendous, annoying ringtone, it’s enough motivation for Sherlock to get out of the handcuffs at take a look. Joan gets out seconds later and they see the message is from Joan’s old friends at the hospital.

At the hospital, a lab tech in the fertility clinic named Abby Campbell has gone missing. She was working late the night before, but her husband reported that she never came home, and her car is still in the hospital’s parking lot.

When examining her lab, Sherlock notices sticky tracks on the floor that suggest a gurney was recently used in the area. They follow the tracks down to the basement that serves as a prep center for cadavers to be used by medical students. Watson thinks a body could have been disposed there, but Sherlock confirms it, matching a chipped tooth in a picture of Abby to the chipped tooth of a skeleton in the room.

Based on the fact that the reconstructed skeleton is missing a bone from her neck, Sherlock determines that Abby must have been strangled, and considering that her lab space faces the door, there’s a good chance she wasn’t jumped by the attacker, but rather knew him or her. That’s when Sherlock mentions that Abby’s husband is an oncologist and clearly a suspect.

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When they question the husband, he insists he didn’t kill her and that, in fact, he was trying to do the opposite. See, Abby actually had Stage 4 pancreatic cancer and had maybe a year to live. He was trying to cure her cancer, so why would he kill her? What would his motive be?

With the husband cleared for now, Sherlock decides to go over the hospital’s security footage to look for anything abnormal. He does this while listening to Rebecca Black in order to infuriate Watson. He also likes the Baha Men, for the record, because “Who Let The Dogs Out?” appeals to his love of mysteries.

What Sherlock discovers in the security footage is that Abby was having an affair before she died. She’s seen meeting with Dr. Fisher, someone who, curiously, has no real address and would have no reason to cross paths with Abby. Could he be the killer they’re looking for?

NEXT: Stem cells and black eyes

Before they can follow the Dr. Fisher lead, Sherlock and Watson get a call from Dr. Campbell, Abby’s husband, about meeting in person. They go to his house and find Dr. Fisher there as well. It turns out that the two of them and Abby were all part of a group marriage, and that Fisher was in Boston when Abby was killed so he couldn’t possibly have done it.

Dr. Campbell does lead them to other suspects though, as he says Abby was once in a more complicated and tense group marriage with five other people. Of those they question, the obvious tension is with Denise, a former partner who pressured Abby to use $100,000 of inheritance money for a down payment on a house for the group. It’s money that Abby never got back and the two have fought over it ever since.

Denise, a lawyer, claims that she and Abby cleared the air though, and shows the detectives that Abby was looking for advice about obtaining a confidentiality agreement. It looks like she was going to sell something, and considering that it may have been illegal, the potential sale may have led to her being killed.

While all of this is going on, a cop named Cortes is also investigating Watson. Although we don’t completely know her motivation, she seems to have disdain for Watson because she’s just a citizen, not a real cop, and pokes around in the lives of other cops. Nothing comes of the investigation yet, but there’s the threat that Cortes is looking into how Watson and Holmes were reinstated with the NYPD, which could come back to haunt them later this season.

When Sherlock and Watson get back to tracking down what Abby might have been selling, they determine it was likely embryos that would otherwise be disposed of by the hospital. She could sell them for upward of $10,000 to the right buyer.

That buyer turns out to be another doctor at a local college who’s working on stem cell research, but he insists he didn’t buy the embryos. Rather, Abby gave them to him in exchange for time in his lab, alone, where she could run blood tests in secret. The lab has since been burnt down though, meaning all the evidence from the tests are gone.

Watson figures that some of the disposed medical material is probably still down at the waste plant though, so they pull a warrant for all of it. When they sort through everything they find six vials of blood with relevant residue and connect the patients to a cancer support group that Abby was attending.

It turns out that Abby was gathering blood from these patients in order to help with an advanced cancer research study. When it’s revealed that the husband of one of the support group patients confronted Abby and told her to stop, Watson and Holmes go to question the man.

While he seems innocent, Watson does find something strange. She does her own test on the woman, who’s diagnosed with a type of spinal cancer, and figures that there’s no way she has cancer, that the diagnosis is way off. And who was the oncologist that made that diagnosis? Abby’s husband.

When they confront Dr. Campbell with the misdiagnosis, he balks at their suggestion and says those things happen and that he stands by his treatment. He has a lot less to say though when they show him dozens of patient files where he’s misdiagnosed them and given them chemotherapy treatment for no reason, other than to potentially “help” his wife, or maybe help his private practice succeed. When Abby found out about the fraud and fixed numbers, she confronted him, and he strangled her to death.

With that solved, Holmes and Watson head back to the brownstone, where Watson ices her injuries after challenging Cortes to a boxing match, which is the way “real cops” settle their differences. It’s a nice way to end the episode, one that moves away from last season’s lingering actions and instead focuses on the reliable dynamic between Watson and Holmes.