Plot

Jane and Maura go undercover at a sex party to track down the perpetrator of a sex related murder in a mansion that's on the market. As Maura and Hope get better acquainted their relationship turns out to be especially important for Hope's daughter Cailin. Meanwhile, Sister Winifred tries to maintain some level of civility in the squad room.—David Foss

Jane and Maura investigate the death of a man who is found in a garbage can outside an empty $3 million home that has been on the market for a year. He's identified as Neil Murray, the owner of an investment company. Maura determines that he suffered a cardiac arrest after being injected with potassium chloride. The investigation reveals that Murray and his partner ran a sex club and it's up to Maura and Jane to now go in undercover. Meanwhile, Maura invites her biological mother, Dr. Hope Martin, and her 18 year-old half sister Cailin over for dinner. Cailin seems very stand-offish but Maura subsequently learns that the young woman is quite ill and in need of a kidney transplant. When Maura learns she is a match, she decides to donate one of her kidneys - anonymously. Her secret is soon out, however.—garykmcd

Investment firm partner Dale Bowman is proud of their services to middle-class investors, but suspiciously uncooperative about the murder of his co-founder Neil Murray, who recruited customers and had his corpse, in party masked costume, dumped in the garbage outside a villa being sold by cahoot Georgette Wilkins, whom an undercover operation proves also procuring prostitutes for sex parties. Meanwhile Jane's mother cooks so Maura can host a home dinner for her unsuspecting globetrotter mother Dr. Hope Martin, whose gloomy teen daughter Cailin had to abandon her London studies in desperate search for a kidney transplant, which Maura wants to be the anonymous donor for, but truth time proves nasty.—KGF Vissers

A man wearing a mask lounges in bed in a robe. A blonde woman wearing a mask comes in wearing lingerie. He's expecting her. He tells her he's "Rodium." He tells her not to be nervous, but she tells him she's been instructed. He's done this many times before. She takes out a syringe and injects him somewhere below. He starts to convulse.

At Maura's house we pause for a little Dr. Scholl's product placement as Maura gives Angela some for her high heels. She's going off to work all dressed up. Jane thinks her mom has a "gentleman caller."

Maura's birth mother Hope calls her suggesting dinner. Maura invites her and her daughter over. Jane's phone rings. "Saved by murder," she says.

Jane and Maura go to the scene, a $3.2 million dollar house for sale. Maura freaks out about dinner and Jane suggests Maura sweet talk Angela into cooking and invite her.

The real estate agent is Georgette Wilkins. The house went into foreclosure a year ago when it was being renovated. She doesn't think it was a murder.

There's nearly a whole ear skewered on a gate and a blood trail. A Mercedes parked across the street is registered to Neal Murray.

The trash pick-up comes. Jane stops them from dumping the can. Neal Murray, minus one ear, is dead inside.

The victim co-owns an investment company. In the morgue, Maura has found a blonde hair. He's wearing a pin that says rodium.

There are needle marks on his penis. He has a heart condition so he couldn't take Viagra, but he could get injections to do the same thing.

Frost and Jane go talk to Neal's business partner, Dale. He introduces Doug and Lori Gatz, the high school coach and nurse. Doug and Dale went to high school with Neal. They're at Campbell High School, waiting for a ceremony in which Neal was supposed to present a check to the school. Dale and Neal helped set up the school's pension. Dale says they have high-end investors and they don't lose money.

At Maura's for dinner, Angela is making gnocchi and wild boar ragù. Hope rings the door bell and Maura has Jane hide the sketch of her mom at the graveside.

Hope introduces her daughter Cailin, whose a polite but quiet teen. At dinner, she says she misses London. She was in school at Oxford.

There's clear tension as Hope talks about them needing to move to Boston. Cailin excuses herself to use the bathroom and Hope explains that her ex-husband had financial issues so she always had to work. Hope excuses herself.

Maura whispers to Jane that Cailin hates her. Jane brings Cailin the rest of her cake, but she doesn't feel like eating. Jane tries to talk to her but she's polite and withdrawn. She thanks Jane for trying to talk to her, but tells her she's walking home, she wants to be alone. Hope gets out of the bathroom and goes after Cailin, saying she's very fragile right now.

At the station the next day, Maura says there was no erectile dysfunction drug in the victim's system. He had a heart attack but she hasn't found what caused it yet.

Hope drops by to apologize for Cailin. She explains that Cailin is very ill, which is why Hope brought her back to Boston. She contracted a bacterial infection while Hope was doing relief work and she's in desperate need of a kidney transplant. Hope isn't a match and neither is Cailin's father. Maura wishes there was something she could do.

Korsak finds an ER record for Neal from a few weeks ago. A rapper named Heavy Drizzle aka Lamar Jones brought him in. He pulls up one of his songs, leading to some really bad rump shaking from Frankie and Frost.

Down in the lab, Jane finds Maura testing last night's dessert. "I think we're a match," she tells Jane.

Maura thinks she can donate anonymously. She doesn't want to make Hope relive the worst event of her life, Maura's "death," by telling her.

Heavy Drizzle and his posse show up at the station. Frankie joins Frost in interview. He says he doesn't recognize Neal, even though he's his business adviser.

He admits Neal was his money man. He wanted liquid capital back and Neal promised Dale would get it. He was speeding with Neal in his car and gave him chest pains, threatening him to get his money back. Neal told Heavy not to tell Dale and gave him the money out of his own pocket.

Frost and Korsak meet with Dale, who tells them to talk to his lawyer. They notices his keychain is like Neal's.

Frost looks through Dale and Neal's financial records and declares them fishy. He says it looks like a Ponzi scheme.

Jane pries open the keychain and finds a flash drive. It pulls up a site for Ten Precious Metals, which displays women. Ten different levels of girls for ten different levels of investors. There's a calendar.

There was a secret sex party at the vacant house the night of the murder and other vacant houses different nights. Georgette Wilkins was the listing agent for all of them. They run her prints from her business card and find she's Candy Smith, a former prostitute. She sold Neal his house.

Neal and Dale were desperate for investors, so Georgette supplied the girls and the houses she couldn't sell. Neal threw the parties and got big investors.

Hope drops by Maura's office. Hope talks about feeling helpless and not able to protect her daughter, again. Maura reassures her. Hope just heard about the anonymous donor. She's worried she's losing her daughter. Maura makes her feel better.

Jane and Korsak confront Georgette/Candy, who denies knowing anything. She goes into a private club so they can't follow. Jane calls Maura to get her in.

Maura has the tox results on Neal: he was injected with potassium chloride.

Jane and Maura follow Georgette into the bathroom. She doesn't know who killed him. They use the same girls every time and the guys sign a release. Jane tells Georgette to hold another party that night.

In the lab, Maura compares Georgette's hair and declares it's not a match to the crime scene. She insists on going to the party undercover.

Cut to Jane and Maura going into the party dressed as buttoned-up waiters. They pull all the blonde hairs they see. Everyone is wearing masks, but Jane sees the coach from the school lift his mask. Georgette is draped all over him.

Maura checks the hairs they've gathered from call girls so far, but doesn't find a match. A little while later, Jane hears a scream and finds Georgette floating facedown in the pool.

Back at the lab, Maura says Georgette was pushed into the pool and hit her head. She's wearing a 4 carat diamond ring, the girlfriend kind.

Maura gets the results from a gel she found on Neal's body. It's from a butane gel used to keep food warm. They realize they should have been testing the caterers. Jane sees a print on the giant diamond.

At the high school, Doug leads a presentation to his fellow teachers advising them to stay with Neal and Dale's investment firm. Jane and Frost come and arrest him. They found Lori's print on the diamond ring, she tried it on before she killed her. Doug stole all the teacher's money.

So Lori the nurse snuck in with the caterers and injected Neal, the man who ruined her life.

Later, Maura's at home when Cailin knocks on her door. Cailin tells Maura her name means "uncertain."

"That's the name that my mother picked for me. Maura means great, that's the name she picked for you," she says.

Cailin shows Maura the news clippings about her and Paddy Doyle and asks why she called her mom. She found the drawing of her mother at the graveside the other night when she went snooping.

"Do you have any idea what it's like to grow up in the shadow of a dead baby? I was never enough," she asks. Maura tells her she wants to help, but Cailin doesn't want her kidney.

"Please don't throw your life away because of me," Maura says.

Hope shows up with the police, Cailin took her car.

Maura tells Hope that she's Paddy Doyle's daughter, and hers. Hope is shocked and doesn't want to hear it. She yells at Maura, then drags Cailin out of there.

Later, Maura cries to Jane. She composes herself then decides she's insulted that Cailin rejected her kidney. Jane tells her she's better off keeping it anyway.