A/N: All of Third Dimension in one chapter. Not a huge fan of this episode, but the end was very important. I tried to explain how snippy Sarah is with Chuck in this episode, why Chuck is so careless and stupid. There is WAY too much Buy More in this episode, and so disgusting I fast forward through it. Also huge chunks of time when Sarah is not with Chuck. Sarah never saw Gambir and yet she recognizes him in the hotel bar, error that I fixed. Three days pass over the course of the episode, but there is a huge gap between the end of the concert and then evening the next night, and Sarah is not there-she shows up at the end. Tried to fix that too. Next up is Best Friend, not Suburbs. I guess they aired those out of order because of a speech or something and kept Suburbs where it was because of Valentine's Day but it doesn't make sense! The end of that episode does not match the beginning of Beefcake.

That Christmas, 2008, was awful.

Not the worst ever, not the worst by far. Before Chuck, they had all been bad. And I would sink to the depths of despair just a year later, when Chuck was in Prague training to be a spy and I was lost and alone. But in terms of the years I was with Chuck, this one was hard. Worse than being away in D.C…if only because I had such high hopes after I accepted Chuck's invitation.

By the end of the day, I actually thought a last minute order to go to D.C. would have been just what I needed. As if being anywhere without Chuck would really have made anything better. Just having the thought shows how bad it was. But still, it was awful.

The very worst of it was I didn't even know why.

Eliminating Mauser had shaken me down to the foundation, made me feel like the agent I had been before, standing on the balcony of the hotel in Lisbon, thinking about how large the splatter would be if I jumped. Cold and dead on the inside once again.

The thought never occurred to me that Chuck didn't listen to my instructions. I don't know why…I mean, he never, ever listened, not when he thought I was in danger…or someone needed help. But in that awful uncertain haze that made me feel so insecure, I never entertained the thought.

It was almost like I thought somehow he had just looked inside me and seen how dark and ugly my soul was. I didn't know why; I just thought that somehow the inside was starting to seep out.

The thing that made it so difficult was the distance between Chuck and me. He was forcing his smiles, brooding when he thought I wasn't looking. Ellie even pulled me aside and asked if I knew what was wrong with Chuck. She was worried that the hostage situation the day before had affected him, traumatized him.

Ellie…always worried about Chuck. By this point, Chuck had a good handle on dealing with the stress of spying. Outwardly, of course it would seem like that to Ellie, so unaware of the other life Chuck was leading.

I knew that wasn't it, but it calmed Ellie down for me to say I thought it was. I lied and told her it had affected me too.

What would Ellie do if she knew the truth? That I had shot that police officer in cold blood? And for all the reasons why?

Chuck was jumpy, agitated even. Restless. His appetite was poor. Morgan, who was there because Ellie had invited him after Anna broke up with him, would talk and Chuck would lose track of what he was saying.

Morgan would comment on whatever episode of The Twilight Zone was on, so excited, enthusiastic about the episodes he knew Chuck liked. Chuck wasn't paying attention.

And even after that heartfelt emotional gift he had given me yesterday, now he barely looked at me. Even though I was seriously dressed down in order to coordinate with the pajamas, I still wore the bracelet. I never wanted to take it off. I would feel my heart bloom like a flower whenever I saw it.

Chuck seemed to look away quickly whenever he would see it on my wrist.

Like he was sorry he had ever given it to me.

I told myself I was imagining it, that I was extrapolating something into the situation that didn't exist.

I argued with myself all day and into the night, and then as I drove home.

I don't think he knew how upset I was. Not that he was oblivious to me, not at all. But first, he didn't know how desperate I was to be close to him. And he was so upset himself worrying about me was the last thing he could focus on.

Ellie was working this New Year's Eve, so there was no party. No nothing really. I asked Chuck if he wanted to have a cover date, you know, for believability's sake. He refused. I think he actually went to bed early. I didn't get to wish him Happy New Year until two days later. No kiss. Just a sad smile.

Chuck went on like this for over a month. Withdrawn, sullen, irritable. I asked him multiple times if everything was okay; each time he yes-ed me. Ellie stopped asking in mid-January, but when I was with her I began to notice she wasn't worried any longer either.

He was using all his strength to pretend for her; she believed the show. Chuck unfortunately was comfortable lying to his sister at this point. But that kind of façade, that amount of performing wasn't sustainable forever. And of course, I took the brunt of Chuck's bad mood.

Looking back now that I understand it all, I know part of that was because he blamed me—or better yet, what I'd done, for it. And by that I mean lying. Lying was what alienated us from each other. Internally, he was grappling with the fact that I was a killer, by profession, by a sworn oath to duty.

Layers upon layers of truth and lies, real and fake. It complicates things so much it's hard to explain. It was my job to lie…he lied to his sister and Morgan. But at this point, he had yet to lie to me. And that was the only time I ever lied to him that way.

The distance between us became painful for me. How he was acting was how one would have expected him to act if we were just pretending it all. But he never acted that way in the past, even when he was with Lou or Jill.

There was only so much pain I was capable of enduring. As a defense mechanism, I fortified the walls around me. I was safer that way, but I was brusque, rougher with Chuck. Icy is a good word. The Ice Queen, pushing him away before he could push me.

At the beginning of February, chaos at the Buy More attracted my attention. Chuck actually activated his com in his watch, something we had upgraded after the incident with Fulcrum. We believed we had once again kept the secrets about Chuck from them, but this was another close call, worse than before. We needed a level of extra protection, a way for Chuck to communicate with us in real time. Chuck informed us someone was in the Buy More with a grenade. I was in the Orange Orange already and I told him I would be right there. Fortunately, Casey was already right there.

I ran in through the back entrance and saw Chuck with Casey, both of them frantically trying to dispose of the grenade. Chuck put it inside a safe, which I then told him he should put inside a refrigerator. Casey then, by himself, wheeled the fridge into the supply closet and shut the door. He told us to get down.

I wrapped my arm around Chuck and pulled him down to the floor while I attempted to protect my head with my other hand. My body was between the grenade and Chuck, which at this point, was the best protection I could offer him.

Surprisingly, with the exception of the burned out closet, the explosion drew almost no attention. There were so many people in the store because of a promotional appearance by Tyler Martin, a popular musician; the noise was ignored by almost everyone in the store. Casey went to grab a fire extinguisher and Chuck and I went outside with the intention of heading into Castle.

We went around the Buy More and in through the Orange Orange. I called Beckman right away. She briefed us on the kind of explosive device it was, used by North African terrorists. As it turned out, Martin had just returned from a tour of Africa. She asked us to go question him.

Chuck was busy fretting over how we were going to get Martin alone. I went to work. The way I looked, courtesy of the CIA, was also handy for attracting the attention of rich men, celebrities, and the like. I could pretend to be a groupie as well as I could pretend to be a run of the mill blonde bimbo. And it worked like a charm. Martin abandoned his fans for the hope of a back room encounter with me.

Chuck, once again, couldn't hide himself and listen to me flirting with Martin. Martin noticed them watching. Fortunately, Casey had a tranq dart and used it to knock him out. Casey and Chuck carried him out of the back room of the Buy More and into the back of Casey's car. I don't know what happened in the Buy More or how it was explained–the man everyone had been waiting to see and get an autograph from just vanishing into thin air–but the crowd dispersed after a while. Martin's manager was looking for him, I know that. We saw him questioning Morgan, Jeff, and Lester as we were leaving. Martin's disappearance may have been suspicious, but Martin was a rock star, and I'm sure his manager had dealt with his unusual proclivities before.

Casey dosed Martin pretty heavily with tranquilizer, then again, his rock star metabolism allowed him to wake from an 18 hours dart in two hours. Casey had scoured the surveillance videos of the parking lot and got a lead on the vehicle the suspect used. We were on our way out to investigate, but we had to leave Chuck in Casey's apartment to babysit Martin. Sure, he had a double dose of tranquilizer, but he had proven somewhat resistant, so we couldn't be too careful.

I hate to admit it, but Chuck's bad attitude in general had made it easier for us to leave him out of things. There weren't any serious, complicated, or involved missions between Christmas and the beginning of February, but Casey and I had been following up on some Fulcrum leads, especially once Beckman realized how close Fulcrum had come, once again, to taking Chuck. The more he was involved, the harder he was to deal with.

My frustration had started to turn to irritation.

Chuck got huffy when we told him to stay put and watch Martin, like insisting he had something better to do, alternate plans that we were keeping him from. He glared at me in frustration. I glared back. I had been trying for over a month to get him to talk to me, and after so long a silence, my patience was worn thin. I stormed out while he continued to wear this indignant look.

Casey and I went to the address Casey had found. He drove. He asked me what was wrong with me while we were in the car. I honestly didn't know what he meant, and I told him so. He implied that I was being a little…bitchy…was the word he used, followed by a "no offense." Most girls might have been insulted by that, but not me. Casey was a straight shooter. If he called you a bitch, chances are, you were being a bitch. And I knew I was. I was completely aware of how my irritation was showing.

All of it was exacerbated by the fact that I missed Chuck. I missed him. Even though I saw him all the time, I missed him. I missed the way he would talk to me, look at me, smile at me. The ease we had just being around each other. But I couldn't admit that to Casey, even if he already knew the whole thing anyway. I told him Chuck was just getting on my nerves. He made this funny sound, like he didn't believe me. It took a while for him to come to terms with the fact that I was serious.

I managed to ask Casey what he thought might be bothering Chuck. Not that Casey was one for emotional introspection, certainly not about someone else's "lady feelings" as he would call them. But there were some things Chuck had talked to Casey about that he hadn't spoken to me about. I was grasping. Casey thought Chuck just needed a day off, that he was starting to burn out.

It wasn't the craziest thing he could have proposed. Bonafide, hardened agents burned out all the time. The career of a CIA or NSA agent was short, like a professional athlete's. The job was too stressful and demanded too much, both physically and mentally, to be sustained for long periods of time. Casey had been close to burn out when Beckman sent him to Burbank. I was burning out in Lisbon when I met Bryce. Chuck was a civilian 18 months ago, with no formal training whatsoever, and we made more demands on him than on most agents currently in the field. Of course Chuck could be burning out.

Only I knew that wasn't it. I couldn't explain it to Casey, sure he wouldn't understand, that he didn't want to try and understand. There was something deep inside Chuck, some strength of character that Chuck never knew he had, until it was needed to do the work that was required of him after he became the Intersect. As stressful as his life had become, he thrived on the work that we did. The most draining aspect was the fact that he had to lie to his family and friends.

This was something else and I told Casey so, that Chuck had been acting strangely since Christmas. That was all I said. Not that Chuck's eyes looked troubled, almost dead, when he looked at me now instead of how he used to look at me before. Before he'd seen me kill, although I didn't know that yet.

No one was there when we arrived. The room was full of stuff, however. Hundreds of pictures of Tyler Martin plastered all over the walls. Homemade bombs, chemicals, electronics. It was the picture perfect lair of a stalker, someone who would have gone after Martin due to a fanatical psychosis. The problem was everything was too neat. Like it was laid out on purpose. Even though some crazy people could be meticulously neat, there was something of their madness visible in whatever it was we were investigating. My time with the Secret Service had taught me that. This was staged to throw us off the track.

We called a team in to gather all the evidence just to be safe, waited around while they cleared everything out. It was a long time waiting, but we finally headed back to Casey's apartment around ten.

Both Chuck and Martin were gone.

There were no signs of a fight, no traces left behind that would indicate they had been taken by force. Chuck and Martin had just…left, even though he was told to keep Martin there. Casey was swearing under his breath while I got on the computer and activated Chuck's tracker. It indicated he was at a hotel downtown. We took off in order to retrieve them both.

Chuck's signal was weak, but still functioning, once Casey and I made our way into the hotel bar. We saw the terrorist that had planted the grenade in the bar while we were searching. I had only seen his picture in the report Beckman had sent, but he had seen Casey in the Buy More, because the second he saw Casey, he ran.

We pursued. He stopped and threatened us with an inside coat lining's worth of live grenades. Casey was ready to shoot him anyway, despite the fact that we would all go up in one massive explosion. My only concern was for Chuck, and protecting him. No way I could do that if I went up in flames. The terrorist warned that he had sent others of his people to get Martin, that he was still in danger. And that meant Chuck was in danger.

The man got away and we ran to go find Chuck.

While we were searching, Chuck used his wrist com to call me. He told us he was on the roof.

Of course, I could have been anywhere. If we hadn't already been at the hotel looking for him, he would have been killed this evening.

We ran as fast as we could. We had Chuck's location pinpointed. Casey got to the hallway first. He saw Martin and shot him with another tranq dart.

There were two armed women that were after Martin. Casey took one and I took the other. I forced her into the glass elevator, kneeing her in the stomach and punching. The one Casey was fighting bounced off of us, but between the two of us we managed to subdue them both.

It was when the fight was over that I noticed Chuck, clinging to the outside of the elevator, which was paused at the 21st floor. If he fell…he was dead. I remember turning around, so horrified I couldn't form words. Casey told me to run down to the lobby. I'm not sure why–there was nothing I could have done if Chuck fell. We couldn't call the fire department, attracting unnecessary attention to ourselves.

Looking back on it now, I think Casey sent me out of there so I wouldn't see what was happening. I have to remember–he heard me scream when I thought Colt had dropped him off the building. No matter how upset I was or how estranged Chuck and I were from each other, he knew better than to rattle me that way.

Casey pushed the proper buttons and got the elevator down to the lobby floor. I ran outside and grabbed Chuck, literally grabbed him, and dragged him in his stocking feet into Casey's car while Casey called for the cleaners. Chuck and I waited in the car for a long, silent, uncomfortable time while Casey instructed the cleaners and got Martin's unconscious form into the car with us again.

Casey was the one who laid into Chuck once we were driving again. Chuck was arguing with Casey like a teenager arguing with his father. I stayed silent, too angry to say anything. I put my life on the line every day to protect him, and he just went off half-cocked and almost got himself killed because why…because he needed a night out? I just didn't understand.

We had to tell Martin what was really going on once we were back at Casey's apartment because he remembered too much of the night, the girls with knives and guns, for us to explain it any other way. He started freaking out, wanting to call his manager. Casey tranq'd him yet again.

This time, Chuck freaked out. He did, however, flash on one of Martin's tattoos that was visible on his back once he'd passed out. Turns out the manager was moving secrets using Martin's tattoos.

Casey spoke ill of Martin, and Chuck defended Tyler, which I thought was unusual. Casey insulted Chuck, telling him he was an idiot.

I told Chuck I agreed with Casey. When Chuck spun around after I said that, he looked like I'd slapped him across the face, that I had insulted him too. I tried to not sound harsh, purposely tempering my voice, asking what he was thinking, that he could have easily gotten himself killed.

Chuck started arguing with me. We were bickering at each other, something we almost never did. He wanted a break from being a spy. But there wasn't one. No such thing. I told him he was a spy, branded for life like the rest of us. My frustration poured out while he was so sharp with me.

What he really wanted was space, something this life hadn't afforded him at all. We watched him all the time, listened to him all the time. No part of his life belonged to him anymore. I knew exactly what that felt like.

Casey tranq'd Chuck in the middle of that argument, before I could finish what I wanted to say.

I finished filing my report on Casey's computer and went home while Chuck was still out. Casey told me he would bring Chuck home when the coast was clear.

Chuck gave me the cold shoulder in Castle the next morning, barely acknowledging my presence, let alone saying good morning. Beckman briefed us on the intelligence compiled after Chuck's flash the night before. Her solution was to use Martin as bait to capture Gambir, the terrorist, at the benefit concert that evening.

Chuck did his usual protesting, of course, hating to put anyone in harm's way for any reason. I tried to explain, but Beckman did her usual and cut me off, her military official way of saying too bad, deal with it.

Once Beckman signed off, Chuck started arguing vehemently once again. The language he used here wasn't random. "His life is on the line because he's a pawn in someone else's game." Chuck related to Tyler, empathized with his plight. Chuck thought of himself the same way.

When Chuck realized we wanted him to convince Tyler, he blew up. Casey snapped at him.

Once Casey walked away, I asked, a little harshly, what was the matter with Chuck.

The veil, that wall he had placed between us, slipped for a moment…and I could see pain in his eyes. But he evaded again, rambling, talking about not sleeping well. Ellie had already told me that he had insomnia after the hostage situation in the Buy More. But I couldn't figure it out, knowing his stress wasn't the same as the rest of them. And his refusal to tell me just made me angrier.

"Chuck, lives are on the line, right now, and if Tyler doesn't help us, then he will never be free of those people, and if you don't help us, then Achmed Gambir gets away."

"And the world becomes a more dangerous place," Casey added.

My irritation and frustration was seeping through. "I don't know what happened to you, but this is our job–not only to protect Tyler but the country and anybody else who needs protecting. We do whatever it takes no matter what. Did you forget that?" Some of my own bitterness, my own struggles with the assassin inside me, was there in those words.

Chuck didn't take it that way, though. He just saw my frustration, my lack of sympathy or whatever he thought. The space in between us created that, worsened that.

"That I definitely didn't forget," he said slowly, softly, staring straight into my eyes. I know what he meant now. I wish I had known then, because I know most of what I said to him was my own way of justifying what I had done to myself, what I had lied to him about.

And I did lie. Because the thought of telling him what I'd done terrified me. I mattered to him, and him learning that could make me matter less. I was tortured with those thoughts.

Chuck walked away from me and agreed that he would talk to Tyler and convince him to perform, in order to catch the terrorist. We watched and listened on the monitor. I heard the words Chuck was saying, how he spoke openly and honestly to Tyler. People needed help, and he could help them, just by being brave for one night. He said he would give anything for that, and I believed him. My heart broke when I heard Chuck say it like that.

What healed my heart again was Chuck telling Tyler that we, me and Casey, were the best, that he trusted his life to us. Knowing what I know now, that was also Chuck's way of processing what he'd seen. I was protecting him. That was the moment he let it go, let go of that horrible picture of me with the gun in my hand that was haunting his dreams, turning them into nightmares.

When Chuck emerged from talking to Tyler, he smiled at me. Not his full smile, but a bit better. At least letting me know he wasn't angry at me any longer. I gave him a tight smile, sure there was more that we needed to talk about that might have to wait for a more opportune time.

We got Tyler ready for his concert. We transported everyone in Casey's car. Chuck went backstage with Tyler while Casey and I went to find Gambir in the crowd. We soon found out Gambir was one step ahead, having paid multiple people in the crowd to dress like him, same hat and same jacket, to throw us off. While we were wasting time in the crowd, Gambir went backstage to get Tyler.

Chuck called me while I was still searching in the crowd. Gambir was outside Tyler's dressing room, probably killing the guards. I told Chuck to stay put, that I was coming. I know he was worried, maybe thinking he was going to die and that would be the last chance he had to tell me the truth, so he started to tell me what was really bothering him.

A loud crash cut Chuck's voice off. I called but he didn't answer after that.

Something in me snapped. I started pushing people away, forcing my way through the crowd as hard as I could. I was on fire, but there were so many people, it was hard to make any headway. The longer it took, the more I feared I would show up and find Chuck dead. And then the blankness, the darkness of that feeling would take over and push me even faster.

I was still running towards backstage when I heard Chuck on my wrist com again. He was headed towards the stage, and he needed help. I made sure to ask if he was ok.

From where I was, I could see them when they came out on stage together. The crowd went wild, but Chuck found me in the crowd with his eyes. Gambir was right behind them. I told Chuck to jump.

He and Tyler dove into the audience and started crowd surfing. I found Gambir in the crowd at the same time Casey did. I disarmed him, then punched and kicked him until he was down. Casey finished him off.

Casey and I waited for the cleaners and stayed to do the appropriate statements and paperwork while Chuck enjoyed the rest of the concert from backstage. He stayed backstage with Tyler and his band until almost four in the morning, when we all went back to Casey's apartment.

They all crashed there after the all-nighter, when I went home to the hotel to get some sleep. Casey said he would take care of everything, and make sure that Tyler got on his flight the next evening.

After lunch, Casey told me orders had come down for another mission later that night, and that I should meet him at his apartment after sundown.

I arrived just as Tyler was hugging Chuck goodbye.

Once we were alone, I made it a point to tell Chuck what a great job he'd done, because he had. He kept Martin safe, even though Casey and I had failed.

I also asked him what was wrong, for what felt like the hundredth time, only, because of what he had almost said while we were on the phone, I was hoping he would finally tell me.

He looked like he was gathering his courage, like what he was about to say was causing him pain on the inside.

"I saw you shoot that Fulcrum agent on Christmas Eve…" he blurted out.

I know he said more, but I went deaf for a second, swallowing my saliva so I didn't choke.

Oh God no….

That was my first thought, fully understanding all the awkward time in between then and now like I had been struck by lightning, imparted with so much knowledge that it almost blacked me out. He saw me for what I really was…a killer, not a real girl, a normal girl. He had hopes, and I'd dashed them. I proved to him that I could never be normal.

"...and when I asked you about it…"

"I lied," I answered. I took a deep breath, closed my eyes. "Chuck, I have to protect you."

He took a step towards me, swearing that he understood that, that I was protecting everyone. But he made it a point to tell me that Mauser was unarmed.

I had to tell him all of the truth, that Mauser knew exactly who he was. That was why I had to eliminate him. I did the best I could not to make Chuck feel badly for being the one who divulged it in the first place.

I told him to take a break. To take as much time as he needed. That meant everything—including time to process. I think he understood that even though he didn't say it.

And he wouldn't let us leave without him. He was in, back. Himself. When I looked over my shoulder at him in Casey's back seat, he was looking at me the way he always had, that tenderness in his eyes.

The bubble of emotion I felt on the inside at that moment was the closest to joy I think I had ever gotten up to that point.

We'd cleared the air, and the issue with Tyler had put it in perspective.

Later, much later than this, when Chuck and I were talking while we rested in between our lovemaking on the train from Paris to Zurich, he told me about this.

How he reconciled the image of me he had in his head and the picture of me killing Mauser. I wasn't normal, but he knew that, accepted that, never ruling out a normal life with me just because I wasn't normal. He knew how much I wanted that, and then he would think that as much as I wanted that, I took the chance of losing it forever to protect him.

He had just done the same thing at that time—killed (or believed he killed) Daniel Shaw to protect me, at what could have been the cost of our life together. That was the last piece of the puzzle for him.

Maybe for me too. We both wanted a life together, but were willing to sacrifice that to protect the other. It was why, in the end, Chuck ran into hell to pull me out instead of trying to keep me from going there in the first place.

He believed I was worthy of all of that. I mattered. The quality of the people that you matter to is important, the most important thing.

On my darkest day, remembering that I mattered to him saved me once and for all.