Since Chuck had to go to work to do a CPR test, you went along with Sarah and Casey to the event. They had you stand outside the doors and pose as an attendant and watch for people to see if you would flash on anyone.

"Anything Y/N?" You heard Casey ask.

"Haven't flashed on anyone yet. You guys should be okay."

A man though was able to slip by you without you noticing.

You kept waiting outside just in case until you started to hear a commotion. You turned around and saw Sarah run out and the Casey run towards you. You saw smoke in the room. The poison was released.

"Oh my God. Casey!"

"You stay out there Y/N! Don't come in! Hazmat crews are coming! Call Chuck now!" Casey shouted before slamming the doors shut.

You stood there shocked and then quickly pulled out your phone.

"Come on Chuck pick up."

"Hey Y/NN. Everything okay?"

"No. No it's not. Someone must have slipped by me. The person who had the poison. It's been released."

"Oh my God. Are you okay?"

"I'm okay. I'm not in the room. Sarah got out too. But Casey is still in there with a bunch of other people. Hazmat crews are on their way. They have an hour, maybe less. Baby, I know you don't want to do this but you gotta get to Jill. See if she has an antidote."

"Y/N you know she is not going to want to see me."

"I know. I know. But you got to think of something. Some way to get her to come here. Please?"

"Alright. Alright. I'll do it. But only because it's you asking."

"Thank you. See you soon. And hurry Chuck."

"I will. Stay safe."

Chuck finally arrived, along with Jill. Chuck saw you and wanted to grab you and kiss you, thanking God you were okay, but Jill doesn't know about you two. Chuck may have told Jill about being apart of the C.I.A. along with you but he didn't mention about the two of you dating since right now he has to pretend you're just friends. But by the end of today, you could tell her.

"Y/N! What's Casey's status?"

"I just radioed him. He has about 15 minutes. Maybe less."

"I have to go in there. Okay, I need a Level A Hazmat suit right now." Jill said.

" We don't have those suits yet. CDC will be here in ten minutes." A man replied.

" We don't have ten minutes. I'll go in without one."

"Jill, it's too dangerous." you said.

" I'll do it." Chuck said.

"Wait what? Chuck..." you said, quickly turned to look at him.

"Chuck, whoever goes in there has to be able to make the antidote. That's me." Jill replied.

" Well, is it something you could talk me through?"

" I guess."

" Okay, well, then I'm going in."

" No, Chuck, wait!" you called out.

"Are you sure? " Jill asked.

"Yeah. I'm sure."

" Okay. Okay, uh... . I'm going to have to inject you first."

" Uh... Oh, that's a big needle."

" Ready?"

You looked at Chuck and held his hand.

"Yeah. Yeah..."

"Okay this is a modified version of the viral strain. Now your body metabolizes the poison and the antiviral serum is going to be created from your blood."

"Poison? Poison? ! I thought I was getting the antidote? You just gave me poison?"

"Chuck It's the only way to make the antidote." you said, giving him a smirk.

" Did you not understand that?" Jill asked.

"Oh, that. Of-- No, I understand that whole part. And you." Chuck said now turning to you. "I forgot you went to UCLA for that. You're real good at it."

"I was real good at biochem." you said, giving him a wink.

" We're living on the edge. Love the rush. Oh, damn."

You walked over with Chuck before he went in.

"Be careful in there babe." you said quietly, so Jill couldn't hear.

"I will. Stay out here with Jill." Chuck quickly kissed your forehead before walking in.

You walked back and stood next to Jill.

"So you're the infamous Y/N Chuck always talked about in school."

"That would be me."

"And you went to school for the same thing I did?"

"I did."

"But now you're in the C.I.A."

You turned and looked at Jill.

"How did you...?"

"Chuck told me everything about you two working with the C.I.A."

"Oh! Okay then."

"So how did you two wind up joining anyways?"

"It just kinda...fell into our laps."

All of a sudden, you heard Chuck's voice come in through the radio and you grabbed it.

"Chuck, what's happening?" you asked.

" I need-- I need help right now. Casey's fading fast! The just gun dropped! And it shattered!"

"That was the only syringe!" Jill said.

"Okay, uh, stay calm. I'm-I'm going to find another with Jill."

"Please hurry. We're running out of time."

There was only one hazmat suit available so you let Jill go in while you waited outside.

You looked over and saw Sarah coming up beside you.

"Sarah! You okay?"

"I'm okay Y/N. Are you?"

You nodded.

"Heard anything from Chuck yet?"

"No."

You both then looked over and saw Chuck and everyone else coming out. All okay and healthy.

Everyone was clapping and cheering. Jill all of a sudden grabbed Chuck and hugged him. Chuck was okay with that but when she then tried to kiss him, he quickly found a way to stop her. You saw that and breathed a sigh of relief.

Chuck looked over and saw you standing off to the side. He went over to join you and you both walked over to a spot where Jill couldn't see you both.

Once you were out of sight, you wrapped your arms tightly around Chuck and he did the same to you.

"Oh thank God. You okay?"

"Yeah. Yeah I'm fine. It's over."

You buried your face in his neck and you both just stayed like that.

You, Chuck , Sarah and Casey were all now back at Castle now to debrief with Beckman.

"Jill Roberts now knows Chuck and Y/N are assets. What do you want us to do about it?" Casey asked.

" I want you to do nothing."

You and Chuck looked at each other then back at Beckman.

"Really?" you asked.

" The assassin Agent Walker shot was a member of Fulcrum. A rogue CIA agent. We don't know the extent of their penetration. If Jill knows something they may make a play for her."

"So, you want to use her as bait?" Chuck asked.

"Chuck we want you to continue to "go out" with Jill. Get all the info you can."

"Wait what? I thought I only had to go on that one date? Now I have to go on more with her?"

"For how long?" you asked.

"As long as it takes." Beckman finished before hanging up.

"Sorry guys." Sarah said.

You and Chuck returned to your place for the night.

"Well...this is going to make us being together a little hard right now." you said, as you both went to sit down on your couch.

"It won't be that bad. We'll just have to be more sneaky for a little. We are spies after all." Chuck said, giving you a wink and you giggled.

"True. It will be kinda sexy, sneaking around and making sure we don't get caught by your ex."

You both started to lean in closer.

"Exactly."

Chuck then finally kissed you. It was quickly turning into a full makeout session when all of a sudden Chuck's phone rang.

"Oh you got to be kidding me." Chuck said, breathing heavy as he leaned his forehead against your shoulder.

You laughed.

"Just see who it is babe."

Chuck grabbed his phone and saw it was Jill.

"Guess the sneaking around begins now." Chuck said.