Carina gets intel on Gaez's party and lets them all know where he'll be. Zondra wonders how they should breach community: disguise or commando entry. Amy gives them a "duh," since it's a party. Covert not necessary. Cut to Carnival in Brazil. The three Cats are all wearing white and looking smokin'. Zondra wants to split up and cover more ground, even though Sarah's not comfortable with that. Zondra (the bitch, remember?) doesn't really care what Sarah thinks. Sarah and Amy stick together, although Amy lingers a little behind and dances happily. Sarah's necklace cam relays the party back to Casey in the van while Chuck goes over the files to figure out if Zondra's a traitor. Casey tells Chuck that it must be nice to want to fix everything, but he's not like that. Apropos of nothing, he says Grimes told him to meet Alex's mom and he was going to, but then let it lie. Back inside, the girls spot Gaez, and want to get the layout of the place from Chuck and Casey.
Morgan and Carina bicker back at Castle, mostly about Alex. Carina assumes Morgan told her he loves her, but of course he hasn't. He says he was going to until her father was thrown from a roof. Anyway, he plans to soon. But Carina thinks it's not even serious. Morgan gets a call from Alex, who's at the Buy More, but Carina won't let him go, even going so far as to block him in with his cane. She tells him to take it up with General Redhead. So Morgan answers his phone and tells Alex he was shanghaied into babysitting an injured agent so he won't be able to make their lunch date. Carina feels Morgan up while he talks to Alex, who is pissed but just says Morgan owes her. He promises to make it up and ends the call with a bunch of kisses. Which is the perfect cue for General Redhead to come in and make fun of him, then tell him about a problem in Rio.
Speaking of Rio, the girls outsmart and attack some big bodyguard types and sneak into a backroom. In the van, Carina and Morgan let Casey and Chuck know that Gaez got a call yesterday, and knows the Cats are coming. In other words: It's a trap. Chuck tells Sarah they have to get out of there, but it's too late: Gaez and his heavies come in, and he asks the Cats to drop their weapons. They all do as we head into commercials.
When we're back, the Cats are all tied up and Gaez asks them if they want to work together with him for Gentle Hand. He needs skilled operatives, and so has lured them here to either accept a career or be killed. Chuck's sneaking in to rescue the ladies, though Casey thinks he's overcompensating for getting "your girlfriend's car blown up." Aha! So it was Sarah's. Casey reminds Chuck that he only has a tranq gun.
Back with Gaez, Sarah reminds him that he's already got one of them on the inside, so doesn't need to convince them all. She looks cuttingly at Zondra, who asks Sarah to go ahead and accuse her outright. Sarah won't. They rehash the old fight, but Gaez stops them and says that maybe the traitor isn't Zondra after all; maybe it's Amy. Or maybe Sarah, the lady who doth protest too much. Sarah asks to at least be told who the traitor is before he kills her. But Gaez would rather just kill her. Chuck notices from the roof what's up and thinks they have to go rescue her. But she pulls a knife to his neck, and holds her own. Chuck jumps in then and creates enough of a distraction to let the girls get up and fight, so they're all kicking Gaez and his men's asses. Even when Gaez is about to get away, Casey shows up and decks him. Sarah lectures Chuck on coming in and rescuing her right when Gaez was about to tell her who the traitor is. Chuck's sorry, so Sarah continues her rant: She doesn't need help with her past or with her missions, so will he please just freaking stop already?! She cuts Chuck down from the rope he let himself into the room on, and he groans.
Back at Castle, General Redhead congratulates Team Bartowski for their great work, but says Sarah is right: There's a traitor in the Cats. Sarah's sure it's Zondra, but Casey's always thought Carina was shifty. Chuck thinks it has to be Amy, because no one's really that perky. General Redhead wants the Cats to stay there at Castle, and she wants Casey to interrogate Gaez for the information on the mole. When she shuts herself off, Sarah tells Chuck she has a job for him. She leads him down the hall.
Upstairs at the Buy More, five minutes to closing time, Alex shows up to see Morgan and is happy and ready to go on a date with him until she notices the lipstick on his collar. Uh-oh. This is going to be a tough one to lie his way out of, even for Morgan. He tries to say that Carina obviously did this to sabotage his date with Alex, but Alex has seen enough. She really wants to believe Morgan, but thinks that it's asking too much for him to have canceled on her three times in a row. He reminds her that she trusts him, but she just replies, "Do I?" And then she leaves.
Chuck presents Sarah with his research into the Milan incident. He says it's not totally conclusive, but if they can figure out who was in Milan... Sarah cuts him off and asks him to stop helping with everything. She uses her secret hand coder to go into Castle and bring down a metal door, leaving Chuck on the outside. Zondra's in Castle, ready to greet Sarah. She thinks it's about time they settle this like real women: in a fight. They kick and battle it out as Casey and Amy head in to question Gaez. Casey says Amy's the "muscle," and she punches him in the face. Sarah and Zondra continue their cage match, both looking awfully hot. Gaez tells Casey he's never heard of the Gentle Hand, and he's just a businessman. Amy applies makeup throughout this, as Sarah and Zondra keep fighting. They get to a stalemate and discuss Milan: Neither of them was there. Turns out, though, that the makeup Amy's putting on isn't makeup. She was just pretending so she could blow powder in Casey's face. Which is exactly when Sarah and Zondra figure out the bad guy is Amy. That's also when Amy shows up and knocks out Zondra. She asks Sarah to join her, and then threatens Sarah, Chuck, and Ellie when Sarah says no. Then she knocks Sarah in the face and fade to black for a commercial break.
Chuck's at the apartment picking up the Cats' stuff, which they left at his and Sarah's place. Ellie comes out and asks him how the reunion's going. He answers her question with another question: Doesn't everyone want friends and family around? He asks if Ellie would have been disappointed not to have any friend or family member at her wedding. She says she would have been, but maybe Sarah's different. She suggests he just take a step back and be understanding, since he doesn't have to fix everything. He asks if he blew it, and she says, "Totally. But I think she still loves you."
Morgan storms back into Castle to get into Carina's thick spy skull that he's in love with Alex and is through being Carina's slave. Carina guesses based on how worked up Morgan is that he really does love Alex. She just figured he didn't, since he hasn't told her. Morgan sees her point, and says he needs to go tell Alex. Carina tries to warn him not to move, but call