Alfredo speaks at his sobriety meeting. Afterwards, Sherlock introduces himself another member, Lloyd who he suspects is there to spy on someone.
A paramedic calms a woman in an ambulance. It stops and the driver gets out. Gunshot. The door opens and a man orders the paramedic out. Another gunshot. Someone gets in the ambulance and drives away with the sick woman still inside.
Sherlock and Joan watch a video of the shooting. He takes a paperclip and finds a bullet that shooter missed. It was a reused bullet. Sherlock identifies the shooter as Wallace Turk, a former suspect in a prostitute's murder. He admits to killing her.
Sherlock follows Lloyd and asks him why he is spying on him. He is not spying on Sherlock, but Alfredo.
The police find the missing ambulance. Bell doesn't believe Turk is the killer. The victim, Maggie Halpern's, body is still warm. He left the body for someone else to kill.
Joan, Sherlock and Bell are at the morgue. Maggie was missing some organs, but they were removed before she was killed. Sherlock believes she was a drug mule.
Joan and Bell talk to her roommate. She says Maggie just returned from Brazil where she underwent gastric bypass surgery. Joan believes that Maggie thought she had the surgery, but the surgeon packed her full of drugs instead.
Joan and Bell talk to Janko, a Serbian drug lord. If he helps them find the "surgeon", they will make sure the drugs stay out of his rivals hands.
Sherlock confronts Alfredo. He has been "stealing" cars with Castle security systems in them. Castle fired him and has been badmouthing Alfredo to his other clients. He gets upset at Sherlock and says they are not friends.
Janko is shot and killed before the drug meet with the "surgeon".
Janko was visiting his mistress when he was killed. Sherlock thinks a rival may have killed him and it may not be connected to Maggie's death.
Dr. Ward comes in to "confess" but wants protection and immunity. He claims it was all Janko idea and tells them where to find his earlier victims.
Alfredo is approached by two detectives. 12 high-end cars were stolen, all had Castle security systems. Alfredo has an alibi.
Joan, Sherlock and Bell meet with the ME. Joan examines the stitching on the two earlier victims. She believes Dr. Ward is the surgeon.
Ward and his lawyer come to the precinct. They accuse him of being the mastermind. He confesses.
Alfredo is upset that Sherlock didn't stay out of his business. Sherlock says he couldn't because Alfredo is his friend. He fires Alfredo as his sponsor, so they can be friends instead.