Buster's now questioning Lester at the Buy More. He's trying not to crack, saying he's not friends with Chuck, but he has nothing to tell him. He tells Buster to ask Jeff. Jeff says he doesn't rat because his mom taught him that from prison. Then they're being questioned together, and Buster tells them they can't have poker night in the backroom if they don't give him something. They tell him that Chuck's cheating on Sarah with a hot brunette. They don't know anything else about her, so Buster threatens the poker game again. Lester tells Buster that Chuck tells Morgan everything, so that's the nut he needs to crack.
Chuck's at work, leaving pathetic voicemails for Jill. Because we know he never actually works. Jeff and Lester come out and tell Morgan to give Buster something so they can keep their weekly poker game. Buster walks up as Lester and Jeff leave and asks Morgan if he's ready to help. Morgan says he will. He says Chuck's providing service on service calls, and that he has 23 years of best friendship telling him Chuck's the straightest shooter he knows. Buster sees Chuck with Jill, and points it out to Morgan. He instantly recognizes Jill, of course, and loudly says she's Chuck's old college girlfriend. He doesn't like that Chuck didn't tell him about this. Buster says they can keep their poker game and he won't tell Chuck that Morgan was the weak link.
Chuck has convinced Jill to go to the backroom. She gives him three seconds to convince her that what she saw isn't what she saw. He says it's hard because he would have to get into high-level clearance stuff to explain. But when he realizes he's not winning this one, he tells her what happened. He asks if she believes the story and she asks what kind of fruit punch. He's surprised she believes his story since he heard himself tell it and thought it sounded crazy. But she knows Gui was crazy paranoid, so she knows it's a puzzle, with fruit punch as a clue. Chuck tells her he's going to have to blindfold her and take her somewhere.
They walk into the OOSSL with Jill in a blindfold. Casey tells her the lair is not so secret if he invites people to it. But, hey, Casey, at least Jill's not a bad guy, right? Oh, wait. Chuck has Jill explain how crazy Gui was. She wants to know what kind of fruit punch, and is disgusted they didn't get the exact formula. Luckily, if there's a spectrometer, she can figure it out. As she's doing science-y stuff, Casey tells Sarah he can see what Chuck sees in Jill. She determines that the powder is Rootin' Raspberry flavored Hi-C fruit punch. Sarah thinks "high seas," but Chuck realizes it's a music box and he needs the musical note high C. They don't have an instrument, but fortunately for them (and for the world), Casey's voice is like an instrument because he took choir. He belts out a high C (or so I'll assume), and a slot in the box pops open. No one can believe Casey was a choir boy, because it's unbelievably awesome. Anyway, the compartment that pops open contains opera glasses, but Chuck quickly realizes it's a key, and the lock will be at the opera.