Sir William's apartment has a giant medieval model battle scene set up in the living room. Also, tapestries on the wall. And random swords and shields on the walls. I can't imagine why he's having so much trouble getting girls. The apartment appears to be clean except for a locked room that they don't have the key to. Hadley looks to Chase to break the door down, and he tries and fails, winding up groaning on the floor and holding his shoulder. Hadley steps over him, plucks a key from some random spot on the floor, and unlocks the door. "My hero," she smugs. Why do people put up with her? If my co-worker did that to me, I'd shove her in the room and lock the door behind her, then tell her to find a way out if she thinks she's so good with locked doors. They enter the room to find a lot of crazy devil-worshipping stuff -- a pentagram on the wall, a fake skull on a table that might not be part of the room's decor but instead where Sir William stores his Halloween decorations in the off-season, and a ton of electronic candles that stayed lit despite Sir William being out of the apartment for weeks on end. I know they're not real candles and all, but don't they run on batteries? Hadley finds a book of spells or something on a table. The title is Necronomicon. "Our knight is a witch," Hadley says. Except not really, since I'm pretty sure actual wiccans don't decorate their shrine rooms with stuff from the sale rack at Hot Topic.
In the meeting room, the Cottages pour over the props from Sir William's apartment. Taub suggests that Sir William was somehow poisoning himself with his seemingly harmless fake potions, and they didn't see it in his bloodwork because it happened over time, the poison collecting slowly in Sir William's liver in focal hepatic lesions, which is what they saw in the ultrasound. Every time one exploded, it released another dose of the poison into Sir William's system. House has an idea of what the poison could be, too -- lead, from Sir William's many figurines. He orders them to biopsy one of Sir William's liver cysts and test for lead.
Wilson and Sam arrive back at Wilson's apartment on their way to a movie. Wilson wants to change out of his suit, and that gives Sam an idea to take advantage of his temporary lack of clothing to have sex with him. It'll mean they have to see a later showing, but no one seems to mind. Oh, but wait -- House is home. And he's pretending to be cheerful, humming a merry tune to himself as he puts the finishing touches on a plate of hor d'oeuvres, the first part of the dinner he made for Wilson and Sam tonight without telling them about it or checking to see if they had other plans first. Sam shrugs and reaches for one, but Wilson snaps at her not to touch it, no doubt fearful that it contains poison. But House puts on his most sincere apologetic expression and says he's only trying to be nice to make up for his "juvenile" behavior at the dinner. Since when was it considered "juvenile" to do anything with a transvestite prostitute? Except maybe pull on his/her pigtails. Anyway, Wilson and Sam totally fall for it and help themselves.