Sherlock is using a sensory-deprivation tank to battle headaches. Dr. Candace Reed, Joan's former therapist, is murdered, with 50 stab wounds. Her husband said one patient had formed an unhealthy attachment to Dr. Reed. That patient, Alfonse Kapour, jumped off his third-story balcony when he was told the news. Sherlock stole Dr. Reed's backup hard drive for patient records. Sherlock tells Joan it's OK for her to read Dr. Reed's notes in her file. Kapour was in a meeting covered by a non-disclosure agreement at the time Dr. Reed was killed. Kapour's boss, Sydney Place, was also Dr. Reed's landlord. He says she and her partner, Dr. Demopoulus, argued regularly. Joan's sister Lin stops by. Joan looked at Dr. Reed's notes, and she's upset because the doctor thought Joan would be a good mother. Dr. Demopoulus acts defensive when Joan and Sherlock question him. Sherlock finds a listening device in Dr. Reed's office. It may have recorded the murder. Sherlock and Joan confront Place about his having a recording of the murder. He tries to blackmail them about their stealing patient records, but Sherlock doesn't bite and Place buckles. Lin tells Joan that her qualities make her a great detective. Place sends his fixer, Mr. Clay, to see Sherlock, and Clay gives Sherlock his alibi for Dr. Reed's murder. He had destroyed the tape of the murder. He relayed to Sherlock what the killer said afterward, which helped Sherlock identify the murderer. The phrase Clay heard was an old Greek saying. Demopoulus was using the information Alfonse gave him for insider trading. Marcus and Sherlock stay in Alfonse's room to "interrogate" him and bluff Demopoulus into retrieving the murder weapon. Joan is looking into adoption.