The big white house. Gregson walks Watson through the scene, although he's a little surprised that Holmes isn't coming. Bell says the owner is a nine-year-old in Austria who's never seen it. That's hilariously unconvincing. Bell says the place has been cleaned out. No one expects Watson to come up with anything. She looks at some paints, and says she's been reading about art forgery. She's found a jar of a special yellow pigment called gamboge. It's made from some trees in Cambodia, so it's really rare -- and this particular brand is even rarer and sold in only a few places. Bell goes off to do some boring police work off-screen.
London. Two years ago. I like that the previous flashback was "a little over two years ago" and this one is precisely two years ago. Irene leaves her home and Holmes pounces on her. Metaphorically. He really just walks up to her and starts talking quickly. He says it's been several weeks since their sexual marathon, and he's been rebuffed at each attempt to renew it. So what's the deal? She says that their afternoon was unique and can't be repeated, so, "I'd rather just remember it the way it was." She kisses him on the cheek and walks away. Irene has a kind of friendly condescension that I quite enjoy. Holmes offers her another unique experience, and decides to get quite mysterious about it: "If you're not concerned about keeping your clothes clean, I'm quite confident this would fit the bill." She smiles.
Holmes and Irene are in some tunnels. He explains that he's spent a lot of time in the tunnels and catacombs of London. He made his own map and decided there was a stretch that was cut off from the rest. Holmes pulls off some boards that say "DANGER," and leads her into a hole in the wall. They go into a canal that, according to Holmes, "dates back to the Roman occupation of Britain." There are prayer tablets on the wall, and they date back millennia. And Holmes and Irene are the only two people who know about them. Neat!
Modern day. Brownstone. Off-screen, Irene shouts, "NOOOOOOO!" Holmes runs downstairs to check on her. She's on her bed screaming that Mr. Stapleton changed the rules without telling her again. Holmes goes to get some water, but she asks him to sit with her. She wants to know about the last year and a half of his life. For example, why'd he move to New York? Modern-day Irene is devoid of smiles, and she doesn't have the confidence that characterizes London Irene.
Watson gets home, and Holmes wants to know the news. There's not much, but then Gregson calls with the news that the pigment came from a specific specialty pigment store in Tribeca. They sold one jar of it a few weeks ago to a guy named Dwayne Proctor... who recently did five years for assault with a deadly weapon. His PO says he's been crashing with his brother, and the police are on their way to his house. A break!