It's time for Chuck and Sarah's engagement party, and Chuck just can't believe Sarah doesn't want all her friends and family invited, so he invites her old friends, the CAT squad. They're essentially Charlie's Angels, complete with narration by a mysterious "Charlie" character and all. It's Carina, Zondra and Amy -- all beautiful and all spies, of course. Chuck invites them, and they show up, but Sarah's less than happy about it. See, she never trusted one of them, Zondra, and they bicker from the moment the three ladies show up sexily at Chuck's apartment to capture Sarah for her bachelorette party or whatever. (Turns out General Redhead also has an assignment for them, thanks to a flash by Chuck: They need to capture Lou Diamond Phillips and his evil accent while down in Brazil for Carnival. Chuck and Casey are there to guard from the van, and Carina's not there because she hurt her leg, leaving her stuck back at Castle with Morgan.)
In Brazil, the ladies (in cute white dresses) are surrounded pretty quickly, courtesy of a call someone made to alert Lou Diamond Phillips they were coming. Lou Diamond ties up the CATs and offers them all a job. He needs skilled operatives, after all, he says, as he calls them "kitties." It's as creepy as it sounds. While Lou Diamond is making his sales pitch, Sarah accuses Zondra of being with him. She denies it, and just as Lou Diamond's about to kill Sarah she breaks free and asks him to tell her the truth. Chuck busts in and rescues her with his Intersect-fu. Problem is, she doesn't get the info. So she cuts Chuck down all brutally, and General Redhead congratulates them on capturing Lou Diamond, then orders the CATs to stay in Castle until Casey can interrogate them and determine who the mole is. They ultimately determine it's Amy, and Sarah ultimately determines she does need friends; she invites both Carina and Zondra to be bridesmaids and then Ellie to be her maid of honor. Oh, and she and Chuck make up.
Morgan and Alex have a minor tiff over the lipstick on his collar (strategically placed there by a flirtatious Carina, jealous that Morgan's no longer pathetic for her). Alex ends up breaking up until Morgan declares his pathetic love (and we're supposed to believe Alex is just as pathetic, which isn't realistic). She declares hers back, and all is right with the world and their love for now.
A wannabe Charlie voice voices over about nothing at all as we get close-ups of pretty girls' eyes, including Sarah's. He says his spy team, the CAT squad, was the best spy team in the business in 2003. They were: Cold-hearted Carina, the bitch Zondra, party girl Amy, and Sarah Walker, his pride and joy. Charlie's Angels-style opening as we see CAT means "Clandestine Attack Team." FauxCharlie: "Go get 'em, Cats!"
At the Buy More, Morgan's in fantasy land (which is apparently what this intro was) because of Chuck telling him about the Cats. Chuck just hopes these girls still love Sarah, because he's running short on friends for Sarah for the party. Morgan suggests the wild notion of asking Sarah. Chuck says she doesn't want to invite anyone, but he knows she'd want people there, so he's nudging. Morgan wonders what this has to do with him, and Chuck says one of the Cats is Carina. Morgan wonders if she really has to be, because that puts two of his lovers (her and Alex) in the same place. Not good. Chuck just wants her contact info, though, and Morgan obliges. (Her email address, by the way is "Carina_azzkickr.")
Soon enough, we see Carina beating the crap out of some guy when she gets a text. It's an invite for all of the Cats to Sarah's engagement party. Carina quickly calls up Amy and asks about Zondra, getting the whole team back together for their old friend, Sarah.
Sarah and Ellie run into each other in the courtyard -- Ellie's on the way to see her in-laws, the Awesomes -- and touch base on wedding stuff, and the engagement party. Sarah says she's concerned because she told Chuck she didn't want to invite anyone, but now he wants to discuss some big idea with her. She doesn't want him digging into her past, which is a bit complicated. They agree that Chuck tends to dive in head-first. Ellie tells Sarah she can always come to her about complicated family situations, wedding stuff, or anything else. Sarah walks into the apartment, notices Chuck has a bunch of glasses and dishes out, so asks if they're having company. Chuck tells her she is, and offers these two words: "Cat squad!" Sarah looks less than pleased, and then she's full-on angry. He thinks these girls could be her bridesmaids or something, but she says she's changed a lot since she saw them last. She wishes Chuck would have talked to her about this beforehand, and she tells him that Carina? She was the mellow one. Chuck gets that she's nervous, but compares this to searching for and finding his mom. Sarah says you don't know what to expect with this team.
Which is when bright lights come on outside and a muffled voice hollers for Sarah Walker. They walk into the courtyard, and Morgan follows, as a helicopter shines its bright light down on them. Morgan stupidly thinks its Close Encounters or something. Then the three ladies slide down ropes from the chopper into the courtyard. They all take off ski masks and flip their hair around. They tell Sarah they heard about the pending wedding, and that means it's a girls' night out. They'll have her back by noon tomorrow. Maybe. Morgan tells Carina she looks well, and she just walks around him and looks at him. She notices something's different about him, then they all take off. Chuck now sees Sarah's point about the Cat squad: He was not expecting that. Opening credits.
Chuck wakes up the next morning, and Sarah's there in a fancy dress. He talks to her, but she says her head hurts after going to a club in Hollywood, then one in Vegas, then an after-hours spot in Miami. Gorbachev was there. He won't stop talking about how reconnecting with her friends wasn't so bad after all, which must make her want to kill him for so many reasons. She says the squad is not back together, because some of them don't trust each other after an incident where the target they were all after kept anticipating their next move. At the time, Sarah found a hidden transmitter in the heel of Zondra's boot. She denied it was hers, and passed a lie-detector test, so they shook on it and moved on. But Sarah's still not sure. Oh, and by the way, the Cat squad is sleeping in their apartment. Chuck goes out to look, but Carina's not there.
Cut to Morgan's bed, where he discovers her there. Naked. And hitting on him. She thinks his confidence and straight spine are different. She calls him Martin and tells him to get back into bed. He says no, since she totally ignored all of his calls and texts and letters, and now he's off the market. She takes off the sheet and shows off her naked self, so he takes off. He tells Chuck that Carina's an animal and he'll be back when she's gone. When he opens the front door, Alex is there, about to knock. She loves his outfit, and he could easily just explain what's up but instead he pushes her outside and shuts the door behind them. He totally forgot about their breakfast plans, so he sort of explains that he was helping Chuck with the Sarah situation, and that her old friends are in town, blah. Carina comes out then, in a short, silky robe, and asks Morgan to make them some breakfast. Morgan awkwardly introduces Carina and Alex, who's not pleased to see the woman Morgan just described as an "old hen" looking like that. Morgan asks Alex to reschedule for lunch tomorrow, and she tells him twice, pointedly, "I trust you." She leaves and he muses that that seemed like a threat.
Breakfast. Long, uncomfortable silences, which means Chuck has to fill them by asking them about their spying days. Zondra says they're top secret, but Amy's happy to talk about Reykjavik's sulfur baths. Sarah adds some detail, while Carina tries to play footsy with Morgan under the table. Zondra remembers doing shots of snake's blood after breaking out of jail in Pyongyang, but Amy says that was just Zondra and Sarah, who made an amazing team at one point. Chuck tells the story of disarming an explosive device using porn on his first mission. Morgan, now in the kitchen, hides behind the counter from Carina's stares. Zondra and Amy both get a little condescending about Chuck for some reason.
The girls are ready to head out, and Sarah admits to Chuck it wasn't all bad, but she's glad it's over. Zondra throws back another snippy comment about Chuck so Sarah doesn't change her mind. As Carina's about to get in her car (or maybe Sarah's), the car explodes. Carina's fine, but it throws her a ways, and part of the bomb is stuck in her leg. Chuck flashes on it and sees Augusto Gaez. Uh, is it okay for Chuck to flash in front of these ladies, one of whom cannot be trusted?
Anyway, General Redhead Television answers Chuck's question for all of us: Augusto Gaez, in addition to being Lou Diamond Phillips, is the archnemesis of the Cat squad, and he's apparently tracked the Cats down. Gaez is part of an organization called the Gentle Hand that is anything but gentle. The Cats hunted them for years, but could never pin down Gaez. General Redhead gives the Cats a mission to track down Gaez in Rio and arrest him. Sarah would rather do it with Chuck and Casey, but General Redhead says they'll need all available hands. Carina, who's injured, will monitor from Castle. Chuck and Casey will shadow the cats on their trip to Carnival in Rio. Sarah says they're not a team anymore, but General Redhead says this comes from the top: "The Cats are back."
Sarah storms out of the room, and Chuck follows, trying to be upbeat about this all. But Sarah says when she found a tracking device in Zondra's boot, they were on a mission to nail Gaez. Chuck asks if Sarah really thinks Zondra's working for Gaez after she was cleared by the government. Sarah says we'll see. Then Gaez, in a bar, gets a voice-encoded call that tells him they're on their way to Rio. Gaez is happy their plan's working so perfectly.
Amy -- a total ditz -- is so excited about going a mi