Beppo, a thief, breaks into Sherlock's London flat but Sherlock is expecting him. He's seeking a cheap Royal Wedding bust, inside of which is the Black Pearl of the Borgias. At Scotland Yard, Sherlock shatters the pearl, unveiling Lucretia's poisoning ring inside. Joan and DCI Jones, their Scotland Yard contact, have a prickly relationship because Jones is an Ameriphobe. Lola Quinn, a tabloid model, has acid thrown in her face by a robber. Sherlock and Joan send Marcus a cowboy hat, for his new job with the U.S. Marshals. His transfer has been delayed by a federal hiring freeze. Joan is venting about Jones to Kitty, Sherlock's former protege. KItty is now splitting her time between searching for missing girls and being mother to her young son Archie. Kitty has determined that Joan is homesick for New York. Lola is dead after jumping down an elevator shaft. A paparazzi links Lola to Ruby Carville, a newspaper tycoon. Jones warns Sherlock and Joan not to approach Ruby. Instead Sherlock sends Kitty. Kitty tells an oblivious Sherlock about Joan's homesickness. Marcus pushes Captain Gregson to mend the rift with Sherlock and Joan. Marcus figured out who really killed Michael Rowan, the crime to which Sherlock had confessed. Carville summons Sherlock and Joan. Lola was Ruby's biological daughter. She suggests checking out Lola's last boyfriend, who had been abusing her, but he was in a meeting at the time of the attack. Joan finds a two-week hole in Lolo's social media. When confronted by Sherlock, Joan admits she's unhappy in London. Gregson tells Marcus that he's going to miss him. Lola had had plastic surgery. Dr. Halsey performed the wrong surgery on her and the attack was to destroy any evidence. Marcus calls because Gregson has been shot and critically wounded.