At the party, Chuck and Sarah make awkward conversation about love and relationships with Karl and Carina. They're the most obvious liars ever, which I guess is sort of telling since they've always been too good at faking the relationship before. Casey comes in with a wig and moustache, and Carina introduces her "Uncle Johnny, her daddy's brother." Casey: "Kid brother." Karl's glad to meet someone from her family, but isn't sure about the resemblance. Carina: "Daddy and Uncle Johnny share the same thick neck and square head." Chuck's eating baby lamb chop hors d'oeuvres, but Sarah's all focused on where they'll escape to find the vault and when. Chuck tries to talk about this thing hanging over them since Prague. He says he misses her. Sarah watches Karl and Carina excuse themselves from Casey. Chuck goes on that it feels good hanging out as friends like they used to. Sarah says it's just a cover and leaves. Carina watches and heads over to Chuck, asking what the hell he's doing to her mission, since they're supposed to be a happy couple. Chuck says Sarah's been so cold ever since he got back from Prague. Carina calls him an idiot, and says she's been cold because she loves him. She tells him to get his head out of his ass and go be a spy. But he's a little busy being dumbfounded right now.
Chuck chases after Sarah and says Carina said something to him; he knows it's not the best time, but they need to talk. Sarah tells him to focus on the mission, and that Carina's getting the key. In another room somewhere, Carina's giving Karl a pep talk before his toast. They hug and she steals the key from his pocket. Sarah sneaks by and takes it from her. He goes back out and toasts. He says he wants to spend the rest of his life with her. She's real, honest, and good. A toast to the future Mrs. Stromberg. He loves her and kisses her. Sarah and Chuck sneak away. The toast listeners start to break up. Carina asks him if that's it, and he's like, "Uh, no. Also ... may our first child be a masculine child." Weird. Everyone toasts. Chuck and Sarah aren't even to the vault yet, and he's trying to talk to her. She radios to Carina that they just got to the vault and need more time, so Carina calls the crowd back and says her Uncle Johnny's dying to say something.
Casey heads to the staircase and says he's not normally a man of many, or any, words, but he'll make an exception. He remembers the first time he set eyes on Carina, when he was practically still a boy. Cut to Chuck and Sarah, finally opening the vault. Inside are a bunch of moving laser beams. Chuck: "No way." Back with Casey, talking about how warm, kind, approachable, and good at conversation Carina is, and how those qualities are reflected in Karl. Everyone's bored, including me. Maybe they should have made this funnier. Back at the vault, Chuck thinks he can't do it, but Sarah tells him to relax so he'll flash. He thinks they should talk first, so she promises they'll talk later about whatever he wants but he has to do this first. He smiles, then flashes. Then he does this hilariously dorky parody of ridiculous Entrapment-esque spy moves. He does a hand stand, leaps, flips, moves from one side of the room to the other, throws the case back along the ground, and more. When he gets back to her, he tells her now they can talk, but then accidentally touches a laser beam. A door shuts him in. Karl's guys' beeping alarms go off. Chuck doesn't like small spaces, so Sarah tells him to breathe and he'll be fine. She tries to open the door. Gas starts in there, so Chuck says he'll be taking exclusively short breaths from now on. She tells him she'll get him out of there.
She notices a grate and climbs into it, but Chuck doesn't know that, so he starts talking, because he doesn't want to regret not telling her stuff. He babbles about how he's a regular guy, not a spy, that he works at the Buy More. Sarah scoots along in the vents to turn off the gas, as Karl's guys come in and listen to Chuck spill his heart: The decision he made in Prague ... He knows it looks like he chose being a spy over being with her, but that's not what happened. ... How he felt about her was real. ... When Carina told him what she said, those three words he's waited to hear. ... He knows she's probably hurt. The guys are chuckling to themselves, when Sarah drops a lipstick from the vent to distract them, then kicks their asses. She waits until they've entered the vault code, though, so she just has to hit enter. As she does, Chuck says, "Sarah, I love you," and passes out in his arms. She looks like that got to her, even though she only heard those three words. Commercials including one for the season 2 DVD.
Chuck's sleeping off the gas at Castle, when General Redhead congratulates Sarah and Casey for recovering the weapon. She asks how the asset is doing, and Sarah just says, "He'll live." Casey wonders what the weapon is, but General Redhead says that information is above his pay grade, and that Agent Miller will bring it to Langley. They never saw it. She shuts off, and Carina says they wouldn't tell her either. Carina packs up the weapon and asks Sarah if she thought about her offer, as Chuck wakes up and hears it. Sarah says she's still considering it. Carina leaves, and Sarah turns General Redhead back on. She asks her if everything's okay, and Chuck listens as Sarah says it's about Chuck's safety. She thinks that she might be more a part of the problem than the solution with trying to manage his emotions so the Intersect can work. Chuck turns to look at Sarah as she talks. General Redhead doesn't know or want to know what happened, but this is her job, and she needs to get over it and teach him to be a spy. Chuck watches her look sad, and when she turns to him, he quickly looks away but she sees him. So she says it's time to train.
In the training room where he boxed with Casey, she tries to fight him with a bo. She says he has to be a real spy, and he says he is. But she knocks the bo out of his hand, and says a real spy would have flashed on it. She gives him another one and says he would have defended himself. He doesn't try to fight her. She says he can do this, but he says he's too emotional and it doesn't work, and can't they talk first. She says he needs to ignore his feelings, because spies don't have feelings; they get you killed. He needs to bury them in a place deep inside. He ducks a hit from her, and she keeps trying to fight. She tells him to show her his attack skills. He throws down the bo, and says no, "because I don't want to hurt you." She knocks him over with her bo, and says, "Don't worry, Chuck. You can't."
Karl's following Carina to the Buy More. Morgan's leaving Chuck a message that Carina must come to the party (then Jeffster! tell him Chuck can't save him from this lie). Carina walks in, and Big Mike comes out and pep-talks Morgan into going to talk to her. She walks up, calls Morgan "Martin," and asks him to give her broken laptop (actually the weapon) to Chuck. He'll do it on the condition that she come to his party. She says, "Fine, whatever," and then asks him to promise he'll give that to Chuck. She takes off, and Karl and his men follow her into the back. Karl calls her "Smooshy," and wonders if she's getting cold feet. He puts it in the car, and she asks what's going on. He says someone stole something from him, and he's thinking she's a spy. She says it's ridiculous, and she loves him. So he puts on video of Chuck in the vault saying he's not like Carina, a cold-hearted spy who throws around words like love. She mutters she's going to kill Chuck. Karl says he'll take care of that, and grabs the housewarming party flier from her. But he says she's next. Commercials.