Brunch! Mrs. Watson (I don't actually know if that's her name, but I've already got someone named "Watson" in the recap) tells the waiter to bring them whatever's freshest, even though her daughter is still reading the menu. Watson ignores a call, because she is trying to be a dutiful daughter. Mrs. Watson says that Watson's brother is coming to the city, and he's bringing Gabrielle so they can all have dinner together. Watson objects that she's got this job where she has to stay in constant contact with her client, but her mother she asks if Watson's client can't just get another babysitter the next night. Being described as a babysitter annoys Watson, so she answers her phone the next time it rings. The news is that she has to be at Sing Sing at 2:30, because Charles Briggs (one of the 2009 crew) is going to talk.
Briggs thinks it's weird that Holmes thinks he'd consider talking. Holmes calls him the greatest lock-picker in the world and offers him a consultancy, since he needs brilliant lock-pickers who are available. So: how did he get past the Leviathan door and who did he sell the secret to? Briggs says he just did the outer door and that Carter Averill was the one that knew a way past the ten-digit code. After establishing that Holmes will hire him for the nebulous consultancy whether or not his tip pans out, he says that he thinks Carter sold the secret to someone whose alias was Le Chevalier.
Outside the prison, Watson catches us up that Le Chevalier has stolen an original Shakespeare First Folio, Van Gogh's Pieta, and some Greek coins. But no one knows anything about him, so she thinks it's a fairy tale. This, in her opinion is a total snipe hunt. No one's ever caught Le Chevalier! But Sherlock Holmes has never gone after him.
Holmes and Watson go over the Pieta case. Watson says Le Chevalier's got style. Holmes agrees, because he's stealing things you can't just fence. As they study the records, he sees a picture of Peter Kent, leader of the fundraising drive that led to the Pieta acquisition. His cufflinks have silver tetragrams, which means they're made from Greek coins. The same ones Le Chevalier stole. Well, that was easy. And Peter Kent is in phone book! Well, the one on his phone.