A young Hispanic woman prays to the Virgin Mary, gripping her arm and lighting candles. "I know I failed you, but please Lord, please help me," she says.
Someone joins her, she's glad they came back and assures whoever it is that they'll get through it. She has a tattoo of a die inside her wrist.
The unseen person puts a garotte around her neck and strangles her.
At Maura's, they get ready for TJ's christening. Rondo, Jane's CI, shows up in a burnt orange zoot suit with a Christening gift -- a Rolex that he says looks real. He and Tommy met in the café last week. Frankie worries about work, he's no longer exclusive to the drug unit. The headline in the paper says: "BPD cuts to Affect all Detectives."
At the church, Father Crowley is doing the christening, which is awkward because apparently Tommy ran him over in a crosswalk. Tommy spent three years in prison for breaking his legs. TJ's mom Lydia is there. Her fiancé Stuart "Strawberry" Strawbridge shows up, which is news to Tommy. Maura is distracted, she thinks she smells human remains.
They hustle everyone out and open up the baptismal font. There's a young woman in agricultural lime (a powder) inside.
Korsak and Maura check with the gardners, Mateo and his son Samuel, who's going to Britmar, a good school. Another man, Sal, shows them the lime.
Back at Maura's house, Tommy and Frankie start eating the cake with their hands. Tommy worries he'll lose custody of TJ; he hasn't filed the custody papers.
In the morgue, Maura reports the victim is between the ages of 17 and 22. She was wearing a locket of a young girl and her mother. There's a faded receipt in her pocket. Maura sees the die tattoo, it's less than eight hours old and was done with a ball point pen.
Later, Maura shows Jane x-rays of the victim's two spiral fractures, one in each arm.
Jane Googles Strawberry and sees a photo from his work wishing him fairwell as he takes his "new family" to Abilene.
Down in the café, Angela is determined to get Tommy and Lydia back together so she doesn't lose TJ.
Frankie calls Lydia and asks her to come by so she can give her TJ's present, he'll get Frankie there.
Korsak and Frost read letters from their bosses warning them they might be reassigned, maybe back to patrol.
Jane snags a tribal mask from Maura's office and gives it to Lydia as a baby gift, saying it boosts IQ. Jane and Maura talk up Tommy. Lydia tries to find positives in her situation, including that TJ will have brothers and sisters, Strawberry "wants his own kids."
When Lydia goes to leave, Jane invites her out for a good bye evening, saying she's being transferred to Guam. Lydia agrees to a girl's night. When she leaves, Maura announces her ring is fake.
Korsak gets the ink on the receipt to reappear with a hairdryer. It's from Cortez Bodega, which is across the street from the Off 93 clothing factory, the brand of clothing the victim was wearing.
Frost and Korsak take an age progression photo of the young girl in the locket. The manager recognizes her as Isabella, the daughter of a seamstress, Blanca Valdez. Frankie has surveillance footage from the bodega, Isabella bought a candle and pregnancy test. They break the news to her mother.
Back in the station, her mother says she couldn't accept college scholarships because she was undocumented. She doesn't think she had a boyfriend. Maura politely tells her that her daughter was four weeks pregnant. She has the same die tattoo as her daughter, which she says is from the Four Corner's gang, to claim her as property. She thinks the gang killed her.
Maura brings a cold case on Aracelli Ramirez who was killed in 2004.
They think Isabella took her pregnancy test at work, but she didn't have a cell phone, so they think she talked to someone there.
At Jane's later that evening, Jane and Maura throw together dinner for Lydia, laying on subtle guilt about her leaving. She takes to Jane's dog, Joe Friday. Tommy shows up with Rondo, expecting to move a couch. Jane pays Rondo to leave than slips the pot roast to her dog. Tommy and Lydia both find the "bad doggie" adorable. Jane and Maura duck out to get take out, asking them to watch the dog so he doesn't choke. They listen outside the door and hear Tommy mock her ring. Lydia leaves in a huff.
Back at the station,Frost has ID'd a factory worker with gang ties, Josie.
Maura announces to Jane that they need to find away to get rid of Strawberry. Jane ran a background check but he hasn't been arrested. Maura noticed he has dark circles under his eyes, and infers he has bad allergies. Jane realizes this means he can get all the dogs that Lydia is looking forward to.
They find Josie sent a text to Tito saying "the one you like is pregnant." Tito is the leader of Four Corners. They find a series of texts planning to jump Isabella. Tito was on house arrest, but Frankie and Frost go talk to Josie.
She says Tito wanted to sleep with her, but all they did was ink her. She says Isabella's boyfriend was some college boy.
Downstairs, Isabella's mom brings by a college sweatshirt from Brittmore College, where the church gardner's son goes.
Jane and Korsak talk to Samuel. He says he saw Isabella that night in church. His father warned him not to be seen with Isabella or the gang would going to kill them both. Samuel asks to talk to Father Crowley.
They go get him but when they come back, Samuel has hung himself from his belt in the interview room.
Later, Jane gets a hospital report that Samuel is alive.
They look up Samuel's father and find Mateo is a former Four Corner's gang member. They find him praying with wooden rosary beads at the church, they match the ligature marks on Isabella's neck.
He's doesn't deny anything, saying that once the gang marked her, he had no choice, the gang would have killed his son for trying to take her.
At Maura's house, Lydia and Stuart drop off TJ. Tommy brings the dog over and Stuart freaks out, saying he allergic. He runs out, telling Lydia to take a shower. Jane and Maura offer to babysit and urge Lydia and Tommy to head out. They leave for a walk and Jane and Maura share a high five.