Quinn is on a private jet with a man named Edgar discussing the purchase of “The Key.” Edgar tells Quinn he acquired the component from Ted Roark and hands it to him. Edgar tells him it’s all he has to show for working at Fulcrum for 10 years. Edgar reminds Quinn that only someone with the Intersect can use The Key. Quinn confirms he has one but the version he has either kills your memories or cooks your brains and only The Key can fix it. Quinn reminds Edgar to keep that information secret because he still has a lot of enemies out there.

Cut to the jet’s baggage compartment where Sarah emerges clad in a leather spy outfit from one of the larger bags. She packs up her weapons and gear, which includes a parachute. She enters the main cabin while Quinn and Edgar continue to discuss The Key. Edgar reminds Quinn the component is only one part of three needed for The Key to work. Quinn confirms he already knows that. Quinn stops talking and senses someone in the cabin. He asks Edgar if he still carries a gun with him. Edgar confirms he does and shows it to Quinn. Quinn stands up, grabs Edgar’s gun and turns around to find Sarah at the other end of cabin pointing a gun at him.

Quinn tells her he knows she’s upset. Sarah tells him, “You stole my memories and you ruined my life.” Just before things escalate, Edgar presses a button on his chair’s armrest. The plane immediately veers right causing Sarah to stumble and shoot her weapon erratically through the cabin before losing her gun. Quinn also falls to the floor. Quinn taunts Sarah and dares her to reach for the gun, which would expose her to Quinn’s line of fire. Instead, Sarah throws a concussion grenade at the plane’s door. After it detonates, the explosion forces the door open, causing the plane to decompress and send everyone to the floor. Sarah holds on to a chair so she doesn’t get sucked out of the plane but to no avail. She hits her head on the way out and is sent into an unconscious free fall with the ground creeping up fast.

Cut to Chuck waking up to his chiming alarm clock. He turns towards the right side of his bed and finds Morgan lying next to him. Morgan tells Chuck its time to get out of bed despite the fact he’s feeling down and misses Sarah. Ellie then enters the room and tells Chuck, “Get out of bed! You’re getting back Sarah today!” Chuck reminds them Sarah doesn’t remember him or anyone one of them. Just then, Awesome walks in with baby Clara and tells Chuck he can get Sarah back. Even Clara agrees. Morgan tells him every impossible mission begins with James Bond getting out of bed. Chuck, discouraged, reminds Morgan he’s lost his wife, is no longer a spy and is back where he started five years ago – alone and living in Burbank. Ellie reminds Chuck he’s not alone. He has his friends and family. He’s so much more than he was five years ago. Chuck tells them he tried to make her remember him, but it didn’t work. He doesn’t believe he can make her fall in love again. Ellie tells him emotions and feelings are powerful things. If he can find Sarah, maybe he can spark some of those memories. She fell in love with him before, it can happen again.

Back to Sarah falling fast to a certain death. She finally snaps out of it in time to release her parachute over the ocean. Meanwhile in Chuck’s room, he’s reaffirming he can get Sarah back. He reminds himself he’s an impressive spy for hire. Sure, Sarah’s a top-notch spy but they did fall in love once, and they can do it again. Back to Sarah, who emerges from the water onto the beach on the French Riviera. With beachgoers looking at her in puzzlement, she walks in her wet leather jumpsuit past everyone. In Chuck’s room he proclaims, “I can do it. I can get Sarah Walker back.”

Casey sits with Beckman in her office. She assigns him the task of killing Quinn. Casey tells her he’s ready, but Beckman isn’t so sure. She notes Carmichael Industries dropped the ball on Quinn already. She reminds Casey, “Five years in Burbank can turn a man into butter.” He needs to be ruthless because anything less will get him killed. She needs “old” Casey. Her best agent. Back at Chuck’s, he’s formulating a plan with Ellie, Morgan and Awesome to get back Sarah. Ellie tells him it’s simple: “Find Sarah; be yourself.” Chuck wonders which version of himself. Charming Carmichael or Lord of the Nerd Herd? Morgan tells him he should just kiss her, and she’ll remember everything. Morgan admits he’s been watching a lot of Disney princess movies with Clara, but he still believes one kiss will bring Sarah back. Ellie and Awesome think Morgan’s crazy. Chuck wonders how he’ll find a woman that doesn’t want to be found.

Cut to Lester at the Buy More laughing hysterically about whether he and Jeff can find a woman that doesn’t want to be found. Lester whispers to Jeff, “Unleash the perverts.” We cut to the Buy More break room where Lester is summoning all his “perverts,” which are actually a network of interconnected geeks who are able to find almost anyone. Lester communicates to the network via his laptop and monitors Jeff has set up. After some random gibberish, they find out Sarah landed at LAX and is on route to Burbank. In fact, she’s waiting at the Nerd Herd help desk in that Buy More location. Chuck runs out to verify.

Sure enough, Sarah is waiting at the help desk when Chuck arrives. He’s initially overcome by emotion, but he keeps his cool and asks Sarah what she needs help with, but not before telling her how happy he is to see her. Sarah is all business and asks Chuck if she can use Castle. Cut to the inside of Castle where Sarah explains to Chuck that she lost Quinn but knows he’s after The Key. She tells Chuck his profile says he’s good with computers and, she wonders if he can find Renny Deutch who has the second piece of The Key. Chuck gets to work on the search while Sarah looks around Castle. Morgan walks up behind Sarah. She immediately makes a defensive move on Morgan, putting him in a chokehold. She apologizes, and Morgan says he should know better than to walk up behind her.

Sarah wonders what Morgan’s doing there. He tells her at one time he was Chuck’s number one go-to best friend. But then she came along, and things changed. If he were to hand off the title to anyone, it would be her. Just then, Chuck locates Deutch in Berlin. Sarah decides she needs to go there. Chuck asks what her plan is when she finds Quinn. She’ll kill him then disappear forever. Chuck is surprised and saddened but before he can say anything else, Sarah tells him she can’t stay there. She can’t be the woman he remembers her as. All she remembers is being a good spy. Chuck offers his help with finding Quinn in Berlin. Sarah is skeptical because he hasn’t been trained. Chuck reminds her it was she who trained him. Still skeptical, she hands him Casey’s Desert Eagle and asks if he can handle it. Putting aside the importance of the gun to Casey, Chuck confirms he’s ready.

In Berlin, Chuck and Morgan sit in a surveillance van. Chuck holds the Desert Eagle and hopes he doesn’t have to use it. Morgan tells him not to shoot anyone. Part of the reason Sarah fell in love with him was because he didn’t shoot people. Sarah arrives. She’s located Deutch, so they need to follow him. When Quinn shows up, she plans to take both of them out. Chuck and Sarah follow Deutch into a Mexican restaurant that looks exactly like El Compadre, a Mexican restaurant they both went to when they first met. Chuck is amazed by the close resemblance. Morgan tells Chuck via earpiece that maybe Sarah will remember something. Meanwhile, hovering outside above their location is a helicopter with Casey and another unnamed operative who asks Casey, “So were going to just follow these schmucks around? That’s how we’re going to find Quinn?” Casey tells him Chuck and Sarah are damn fine operatives and not to sell them short.

Chuck and Sarah sit in a booth at the Berlin Mexican restaurant. Chuck tells Sarah it must be a sign that they’re in a restaurant that looks just like El Compadre. It was technically the site of their first date. He tells her he was so nervous, but she was so amazing. They talked and laughed. They even went out dancing that night. While Chuck continues to ramble about that night, an uncomfortable Sarah asks him to stop. She tells him to focus on the mission, not their story. Via earpiece, Morgan tells Chuck not to fret. He can try to make this the most romantic mission ever.

Deutch gets up to leave the restaurant. The meet location has changed. As they get up to leave, Chuck tells Sarah they may need a wardrobe change. Cut to a ballroom and Chuck is in a tuxedo while Sarah is wearing a cocktail dress. Sarah wants to get closer to Deutch somehow. Chuck reminds her she taught him how to dance. He grabs her and they start to dance. It’s getting a little hot for both of them, but before anything can progress, the meeting place changes again as Deutch gets a text from Quinn. Cut to Wienerlicious where Deutch has just ordered the special. Chuck and Sarah emerge dressed in employee uniforms. While waiting around for Quinn to show up, Sarah starts to rearrange items on the counter as though she’s worked at a Wienerlicious before, which of course she did. Chuck takes notice and encourages Sarah to try to remember.

Sarah’s concentration is broken when Quinn and his men show up, guns drawn. Quinn then redirects his attention to Deutch. He asks him if he brought The Key. Deutch confirms he did, but it’s going to cost because The Ring spent a lot of money acquiring it. He hands the key to Quinn. Quinn looks at it and then kills Deutch and his guard. He holds up The Key to Chuck and Sarah and exclaims, “One more to go!” Meanwhile, Casey is hovering in the helicopter above the Wienerlicious and prepares to land. Back at the Wienerlicious, Quinn’s men bring in a captured Morgan. Quinn orders Chuck and Sarah to drop their guns. Chuck complies immediately, but Sarah is reluctant. Chuck grabs her gun and reminds her they’ve got Morgan.

Quinn goes up to Chuck and Sarah. He tells Sarah her husband is one of the world’s biggest “pussies” and is about to shoot him when Sarah throws a wooden skewer at Quinn that causes him to drop his gun. A fight begins where Chuck, Sarah and Morgan take care of Quinn’s men while he runs outside. Chuck runs after Quinn on the streets of Berlin. Meanwhile Casey is in the helicopter, but he can’t get a clear shot of Quinn. Chuck gets a clear shot of Quinn, but he decides not to shoot for fear of Sarah disapproving. Instead, he points the gun in the air and fires a warning shot… which hits Casey’s helicopter! The helicopter is forced down and lands in the middle of the street. After landing, Casey realizes he was brought down with his own gun, the Desert Eagle. Casey is not amused.

At Castle, Casey has Morgan handcuffed to a chair. He’s put Chuck and Sarah in holding cells. Casey wants Morgan to tell Alex that he’s going away for awhile. Morgan wonders why Casey arrested his own team. Casey corrects him. He arrested his “old team.” Meanwhile Sarah and Chuck are in adjacent cells, and she’s chastising him for blowing the mission. He had Quinn in his sites and didn’t pull the trigger. He admits he didn’t kill Quinn because it was one of the things she liked about him. After they fell in love, she didn’t want him to be spy. Morgan keeps digging at Casey and asks him why he hasn’t returned any of Alex’s phone calls. Casey admits he got soft, and now he has to be ruthless. He lost his edge. Morgan reminds him his team was his edge. Morgan tells him he’s afraid to admit he’s the best when he’s with this team. Casey gives a big grunt before telling Morgan, “Screw it. I’m in.”

Casey releases Chuck from the holding cell and then walks over to Sarah’s cell to release her and finds her trying to escape. She tells Chuck she’s better off leaving and finding Quinn on her own. Chuck tells her she can’t because of his mother, who’s a spy and standing behind her with a gun pointed at her. Sarah turns around and sees Mary standing there with a gun pointed at her. She greets Sarah with a knowing hello. Ellie barges in on the moment and gets upset with her mom because she has a gun out. Awesome walks in with Clara and covers her eyes. He tells Mary, “What did we say about baby Clara seeing firearms?” Mary apologizes and begins to dote on Clara. She tells everyone she has Intel about The Key. Sarah decides to stay.

Mary begins her briefing and explains that Chuck’s father developed the Intersect as a teaching tool. The Key was created as a matrix to program the system. He split The Key into three pieces and gave each piece to three different people, so any changes would have to be made only after those three agreed. Chuck’s dad gave his piece to someone in the government. If Quinn gets all three pieces together, he could upload Sarah’s and Morgan’s memories as well as adding new skills and information. Ellie grabs Chuck and takes him to the Buy More theater room and tells him that if they can get their hands on the Intersect glasses, they may be able to create a file with memories from their wedding, etc. and upload it to Sarah so she can once again be whole. Chuck is cautiously hopeful.

Chuck gets a call from Casey who tells him Quinn was spotted at the Pacific Concert Hall. Beckman and her Chinese counterpart are there to watch a concert. Casey figures the person in government that Chuck’s dad gave the third part of the key to was Beckman. She must be the target. Chuck gets off the phone and tells Ellie about the Pacific Concert Hall. When they leave the room to go back to Castle, it’s revealed that Jeff and Lester were behind the couch and overheard the whole conversation. At the concert hall, Beckman is seated and enjoying classical music when Quinn comes up to her. She tries to get up, but he tells her to sit still because the bomb under her seat is pressure sensitive. She looks under the seat and sees a huge bomb. Quinn then takes off one of her medals, which turns out to be the third part of the key. The designers gave it to her for safety. He tells her, “And all those years you never knew it was the third part of the key.” Just then, she gets a call from Chuck, but Quinn takes the phone and answers it instead. He tells Chuck, “It’s over. I win.”

Chuck, Sarah and Casey arrive at the Pacific Concert Hall. Chuck examines the bomb and figures out it’s tied to the performance, meaning as soon as the music stops it will detonate. Beckman orders Casey to get everyone out of the hall. Casey refuses, telling her, “With all due respect General, shut up. We’re saving you.” Chuck and Casey find the “brains” of the bomb, but it’s locked in a box. Meanwhile back at Castle, Mary and Ellie are monitoring the situation and see Quinn walking up to the roof. They tell Chuck, Casey and Sarah. Chuck and Casey stay while Sarah goes after Quinn. Ellie reminds Chuck that Quinn has the Intersect glasses, and they’re going to need them to get Sarah her memories back. Chuck runs up to the roof to get the glasses and to make Quinn disarm the bomb.

On the roof, Quinn tells his people he’s ready for extraction. The helicopter is three minutes away. Back in the hall Casey tells Morgan the bomb goes off when the music stops and to think of something. Just then, Jeff and Lester show up and ask how they can help. Casey is flummoxed at the sight of the pair. Morgan tells him he has a plan. He’s not going to like it, but he has a plan. Back on the roof, Sarah finds Quinn and is about to shoot him when Chuck arrives and tells her not to because he’s needed to disarm the bomb. Quinn laughs and tells them there’s no disarming the bomb because it’s going to detonate when the music stops, and that will happen in a few seconds…

The music doesn’t stop because as soon as the orchestra is done playing, Jeffster starts to play their rendition of “Take Me On” by A-ha. Quinn is confused and wonders what’s going on. Chuck says, “One word. Jeffster.” Jeff and Lester appear on stage to a confused crowd. Lester starts to sing and for the time being, the bomb detonation is postponed. On the roof, Chuck tells Quinn it’s over. Quinn responds with “then we die together” and attempts to pull out his gun before Sarah shoots him dead. Chuck grabs the Intersect glasses next to Quinn’s body and tells Sarah he had a plan to restore her memories and her life with the glasses, but since there’s only one download left in the glasses, he has to use it to get the information to disarm the bomb. He puts the glasses on, and once again, Chuck is the Intersect.

Chuck and Sarah race into the concert hall. Morgan is now conducting the orchestra who are now accompanying Jeff and Lester. Chuck flashes and manages to open the box holding the bomb controls. There’s a laptop in the box. Chuck thinks it may take awhile to configure it. Sarah then suggests loading it with the Irene Demova porn virus. Chuck is shocked because that was from five years ago. It means some of Sarah’s memories aren’t entirely lost. Chuck quickly gets the virus on his smart phone and manages to upload it to the laptop. The virus manages to disrupt the operation, and the bomb is disarmed. Jeff, Lester and the orchestra stop playing, and the audience gives them a standing ovation, not realizing they were a few musical notes away from being vaporized.

Back at Castle, Beckman is congratulating the team. She thanks them on behalf of the U.S. government. She asks if this is the end of Carmichael Industries. Chuck confirms that it is, but Sarah interjects and says it’s really her fault. She needs to go out there and find herself. Casey adds, “We all do.” Before leaving, Beckman tells them, “If you ever want to save the world again, you know where I am.” Before anyone can say anything else, Casey looks at his watch, then gets up and says he has to go. Chuck, expecting a more substantial goodbye, is a little taken aback. Casey tells him, “You expect me to get all weepy and emotional? I’ll skip that part.” Casey tells him he’ll see him when he sees him. Chuck puts out his hand to Casey, but instead Casey gives him a big bear hug saying, “That’s one thing Russians do well, give good hugs.” He shakes Sarah’s hand and walks out of Castle.

Now alone with Sarah, Chuck tells her remembering Irene Demova was perhaps a fresh start. Sarah doesn’t know what it means. She tells him she needs some time to think and to be alone. She apologizes to Chuck who’s obviously devastated that he may be losing her forever. As she turns to leave, Chuck begins to tell Sarah about Morgan’s kiss theory… but stops. Sarah walks up Castle’s stairs and leaves. Back in the Buy More, Jeff and Lester are telling Big Mike about their life-saving performance at the concert hall. Mike doesn’t believe a word of it. But Mike is excited about the new owners moving in. Subway. He’s excited because he’s now going to be eating fresh. Just then, a “very important record executive from Germany” who saw Jeffster perform at the concert hall approaches Jeff and Lester and tells them they’re going to be big stars in Germany. He tells them, “Women and man will adore you.” The producer wants them to leave the store and go with him. With a tear in his eye, Lester asks Jeff if he’s ready. Jeff tells him, “Let’s rock” and they leave the store with the producer.

Back at Casey’s place, Morgan and Alex have just finished telling him they’re moving in together. Casey isn’t surprised because, as he reminds them, “Hello? Spy.” Casey gives them the key to his place and tells them there’s someplace he needs to be. Morgan figures it’s to go after Verbanski. Casey tells Alex he was going to ask her if it was okay, but she tells him he doesn’t have to. He deserves to be happy. He should just go. Alex gives her dad a huge hug. Casey smiles. At Ellie and Awesome’s, they’re packing for their Chicago move. Ellie is talking to Chuck and feels bad that she’s leaving Chuck now with all that’s happened. Chuck tells her she’s taken care of him long enough. He’s all grown-up now. Awesome asks Chuck about Sarah. He answers, “I don’t know.” Chuck and Morgan discuss the whereabouts of Sarah in the courtyard. Chuck thinks she can be anywhere. Morgan reminds him that Chuck once told him to “listen to your heart because our brains always screw us up.” Morgan tells Chuck to stop thinking and listen to her heart, figure out where Sarah is.

He finds her on the familiar beach and they talk. She asks him to tell her a story and he does — their story together. As he does, we see flashbacks of the last five seasons. It looks as if she may be remembering some things but it’s unclear. Chuck notes that Morgan had this crazy idea that, if he kissed her, Sarah would get her memories back. She asks him to kiss her and he does, for a very long time.
Synopis courtesy NBC.
First aired: January 27, 2012.