He takes his beard, robe, slippers, and an added trucker cap and sunglasses to the Buy More, looking very much like a creepy pedophile. Jeff greets him as "Sir," and asks how he can service him. Chuck deepens his voice and says he's looking for cheese puffs. Jeff robotically says, "Aisle 3. It's been a pleasure serving you." He walks off and Chuck realizes how well the disguise is working. So well that Buster Bluth, watching Chuck approach the cheese puffs via security cam in his office thinks Chuck's a homeless person. He calls security to Aisle 3, saying there's a street person, and he might be the one stealing toilet paper from the bathroom. As Chuck heads off with the cheese puffs, Buster stops him. Chuck removes his sunglasses, and Buster seems delighted to see it's "Bartowski!" He walks around him, then calls everyone up to get a good look at how the mighty have fallen. He says Chuck smells like the putrid scent of failure. He calls him a loser, and pathetic. Chuck keeps flashing on him as Buster calls him a hot mess. Chuck grips the cheese puffs, so as not to unwillingly kick Buster's ass, but then he tells Buster he's fine, and Buster says that's good, because he almost kicked Chuck's ass. He walks off, and Jeffster! approaches. Lester calls Chuck "O Captain, my Captain," and asks him if he returned to take control of the Buy More. Probably not in that outfit. He apologizes that he doesn't think he could help even if he tried. Lester thinks he probably wouldn't care since he still has Blondie. Jeff says she's getting hotter, and they tell him they still see her at the Orange Orange. Chuck's happy to hear she's still here, so he heads next door.
He unlocks the door and walks in, but Casey knocks him out. He lands in a pile of his cheese puffs and then Casey calls him a "lemon" and "pathetic." Wow. That's a lot of insults for our hero to endure so soon into the new season. Chuck says he came to get a light jacket he might have left downstairs. Casey sniffs Chuck and makes a disgusted face, then tells him to pick up the puffs. Downstairs, Casey tells Chuck to hurry since he needs to finish packing. Chuck asks, fake casually, if Casey's talked to Sarah. Casey says no, and then his phone rings and Chuck sees it says "Agent Walker." He's like, "Can I talk to her when you're done?" Casey, on the phone, just says, "Yeah. So. Yeah." Chuck interrupts to ask if Sarah got any of his messages, and Casey says into the phone that "It's the lemon." Then, "Duly noted." He hangs up and says Sarah didn't say anything about Chuck. He begs to go on a mission with them, since he can still flash. He just needs to prove it to General Redhead to put the old team back together. Casey snarks that then all of his dreams would come true. Casey pulls up some stuff on his spy computer. It looks like a map of a place called "El Bucho" and a menu from the same place. Chuck says he's heading out. Casey tries to ask what happened between Chuck and Sarah, but Chuck just says, "Something I need to fix."
At home, Chuck shaves, showers, and gets dressed in his old Nerd Herd outfit, pocket protector and all. He arrives at El Bucho and gets in by telling the guys at the door that someone called about a computer emergency: "Sound board's down." That really is a good cover. Everyone trusts a geeky computer guy. Chuck gestures at Casey as he comes in, and Casey radios to Sarah that they have a situation. She sees Chuck, and comes over to him, asks what he's doing there. Chuck says not to worry. He's just here as backup, to prove to Agent Redhead. But the guy from next to the pool walks in, and Sarah asks Chuck to kiss her. He wonders if they shouldn't talk first, but he insists. So he does it. Then she pushes him away and slaps him so hard he falls to the ground. The pool guy walks up and asks who the hell that is. Sarah says it's just her ex, who's having some trouble letting go. So mean, but maybe he deserved it.
In a food pantry, Casey asks Sarah why she knocked him out, and she says, "It was a slap." Chuck protests that he was caught off-guard on an empty stomach. He says he can take a punch, and Casey says, "You mean a slap." Chuck says he's sorry, and didn't mean to screw anything up. He's just here to help, and thinks he can be a spy even though things went wrong in Prague. He looks at Sarah and pleads with her, but she tells Casey to get him out of here and leaves. Chuck asks Casey for a chance, but Casey says it's a simple courier exchange. He says the guy with Sarah is the mark, and he's meeting with a major Ring operative tonight. Chuck reminds us that the Ring killed Bryce. Casey says the moment the Ring guy meets with Sarah's fake boyfriend, they'll strike. He tells Chuck to get out of here before he spooks Javier Cruz, the courier. Chuck flashes on the name Javier Cruz, and sees that he's an international assassin. Casey leaves, though, and tells his guys to get rid of Chuck. Chuck's screams that Javier's not a courier are met on deaf ears as he's led out. Casey, in the other room, tells Sarah he dumped the lemon. Chuck's locked out in an alley, and trying to get in. He loses his pocket protector nametag in the alley as he tries to flash on the door. A guitar player walks up right as Chuck flashes on the door, so Chuck accidentally kung-fu kicks him unconscious. He apologizes, but then has an epiphany.
He walks back into the place in the guitar player's jacket and with his guitar. Someone sees him, says he's late and ushers him on stage, ignoring his request to use the restroom. On stage, another guy in the band asks where Manny is, and Chuck says, "Spastic colon. I'm filling in for him." Nice. Chuck awkwardly kicks his guitar case shut and starts making "Mah, mah, mah" sounds into the mic. Casey tells Sarah he's going to blow the whole op, but she says to give him a second. Then Chuck flashes on the guitar and starts playing. Sarah's fake boyfriend asks if that isn't her ex, and she says, "Yeah, he's a bit of a show-off." Chuck mouths "assassin" to Casey, but when Casey asks where, Chuck just shrugs. The fake boyfriend offers to take care of Chuck, but she says no, and asks him to come dance. Chuck watches them dance, and then fake boyfriend asks how he knew Sarah was here and who is he anyway. She says he has nothing to worry about and they dance sexily as Chuck gets more and more frustrated on stage. Casey tells someone to tranq him, but he ducks and they tranq a member of his backup band instead. Outside, the guitar player Chuck knocks out wakes up and removes his moustache and wig. He heads in and points a gun at Sarah and her fake boyfriend. Chuck sees the gun's laser and jumps off the stage to save her. Everyone jumps up, and he says there's an assassin. Casey and Sarah are pissed he blew the whole thing since half this place was undercover agents. Chuck swears there was an assassin, but Sarah tells him he doesn't work anymore, and it's over. Some boots (either the fake guitar player/assassin or Sarah's fake boyfriend, who disappeared in the melee) find Chuck's pocket protector nametag outside. Uh-oh.
Next morning, Ellie's happy to see Chuck shaved, but he says it was a rash decision. He sits down in front of the TV with his cheese puffs. Ellie says she can't bear to watch him wallow around like this and leaves the room. Awesome comes over and tells Chuck he's really nailing the loser cover. Chuck assures him this is not a cover; he was fired and isn't a spy anymore and isn't sure he ever was. Awesome asks if this is really Chuck, and Chuck says yes, he's Chuck Bartowski, total loser, cheese ball addict. Awesome asks if the CIA lets you just quit like that. He thought they'd send someone to kill you or something. Chuck laughs that Awesome watches too many movies, but when Awesome leaves, you can tell Chuck's a little worried.
Later, Chuck's asleep in front of snow on the flat-screen TV (which is impossible, right? Those TVs turn snow into a blank blue screen or something?) when Morgan shows up and wakes him. Chuck's clutching his cheese ball barrel, by the way. Chuck freaks out, "Don't kill me!" until he realizes it's Morgan, who just wants to cheer him up and find out what's going on. Morgan, by the way, is in his Benihana uniform, which is odd since he's not even in the same state as his cooking school, right? Anyway, Chuck tells Morgan that he had a great job opportunity and he's already been fired from it twice. Morgan says that's amateur hour and doesn't come close to rock bottom. He takes Chuck to the Buy More, and says he got canned from Benihana two weeks ago and Anna took off with the prep chef. "Couldn't flip the shrimp," he says. "Couldn't flip the shrimp." He leads Chuck into the screening room at the Buy More, where he's apparently been living. Buster's watching on the security cams, though, and realizes it must be Grimes who's been stealing the TP, since it looks like he lives there. Weird he wouldn't have noticed the bedding and piles of crap before now, isn't it? Buster says he should have known Morgan couldn't make it in Asian business culture, and he'll let the authorities deal with him tomorrow.
Sarah's also watching it on a different security cam in Castle, when Casey says he's going to miss this. She asks what, and he tells her about some gun that shoots 3,400 rounds a minute and that he never got to use. Sarah shuts off the cam she's watching Chuck on, and Casey tells Sarah the poor bastard is still in love with her. She promises Casey that he's not. Casey says he doesn't know what happened between the two of them and doesn't want to, but he's seen people having their fingernails pulled off be treated more humanely tha