Catherine rolls over in bed and realizes Mark is still not home. She sighs, she had a rough day and really wanted nothing more than to have Mark hold her in his arms, he always makes her feel so safe. She picks her phone up off the nightstand and sees no messages from him. She really hopes everything is ok. He has been so stressed over whatever cases he's working on. She knows he doesn't want to talk about it and honestly she's been so busy that she hasn't had time to know what anyone else on the team is working on. Catherine rolls over and tries to go back to sleep.

Back at the lab …

Brass walks into the ballistics lab and says, "Guys I love you both but this better be worth waking me up and bringing me down here."

Mark responds, "Oh it is we found out who the gun in Eddie's case was registered to."

Brass interrupts, "Wait I know I just woke up but the gun wasn't registered to anyone, that was part of what closed the case prematurely."

Sara speaks up, "Well we started going over all the evidence and we were getting nada. Mark was looking at the gun under a magnifying scope and found what looked to be abrasions near the serial number. He called me over to verify but I noticed the abrasions were actually a flaky substance that was collected but hasn't been run through trace yet. Mark noticed just as I was leaving to run the substance through trace that there was a difference in the metal around the serial number and the gun. Mark got a theory that the serial was tampered with by a small piece of metal containing a serial number was somehow glued over the real serial number."

Mark takes over, "However whatever this adhesive is was covering up the real serial number. So we grinded it down and used acid to reveal the real serial number and Sara ran it through the registry database and well, look." Mark turns the monitor towards Brass.

Brass looks at the monitor and sees why they woke him up; the gun belongs to Undersheriff McKeen. Now they have everything they need to question the undersheriff without raising suspicion.

Brass says, "I always knew this guy was dirty. We need to present this to Ecklie. But Mark this is where you get to do what you've been wanting to do, call Cath and bring her in she needs to be up to speed on this. You can tell her one on one or we can all tell her together your choice."

Mark nods and responds, "Let's do it together. This wasn't just me. If it wasn't for you Brass, we wouldn't have even gotten this far."

Mark pulls his phone out of his pocket and dials Catherine and says, "Hey Cath. No everything is fine. Can you come back to the lab, we've had a break in a case and we need to bring you up to speed it's really important."

Mark puts his phone away and says, "She's on her way. Want to do this in the conference room?"

Brass and Sara nod.

About a half an hour later Catherine joins everyone in the conference room.

Catherine asks, "Hey guys what's up?", as she takes a seat across from Mark, Brass and Sara.

Brass starts, "Catherine I unofficially opened Eddie's case back up. I approached Mark a few days ago and asked if he would help me. I got suspicious of the undersheriff pulling the plug so soon, especially when I found out he has ownership in Sin City Records."

Catherine looks at Mark and asks, "This is what has had you so on edge?"

Mark looks up at her and nods.

Brass continues, "Anyway Mark found a large amount of money going out of Eddie's account several times a month up until about a month before he died. I recognized the account; the money was going into an account at a local bank. We got it traced to a local PI, Sparky Miller."

Catherine asks, "Why did Eddie hire a PI?"

Mark replies, "Well, Eddie didn't actually hire him. Eddie went to McKeen and McKeen asked Sparky to follow you. Eddie was just making the payments. Sparky and Eddie have never met as far as we can tell. Apparently Sparky does work for McKeen from time to time. We don't know why Eddie was having you followed, we suspect that it has something to do with his displeasure of our relationship."

Catherine asks, "Wait, I was being followed and you didn't tell me about it? How long have you known?"

Mark replies, "Only a few days."

Catherine raises her eyebrows with a very evident scowl on her face.

Sara notices the tension and takes over, "We wanted to make sure we had all of our ducks in a row before informing anyone because of the apparent and well now confirmed involvement of the undersheriff."

Catherine says, "Just his involvement with the PI really isn't enough to go on."

Mark takes back over, "Well, Sara and I were going over the evidence again and discovered that the serial number we ran on the gun was a fake. We removed a metal piece containing the serial number we originally ran which was placed on top of the real serial number."

Catherine asks, "What's wrong? Whom was it registered to?"

Brass clears his throat and replies, "McKeen. We're going to have a meeting with Ecklie to decide how we should proceed. I hope we can bring him in right away. Would you like to observe?"

Catherine says, "Of course."

Brass looks at Sara and says, "Uh Sara can you join me in my office for a bit?"

Sara replies, "Sure."

Brass and Sara exit the conference room leaving Mark and Catherine alone.

Mark looks at Catherine and says, "I wanted to tell you I really did."

Catherine stands up from the table and crosses her arms, "But you didn't."

Mark sighs and runs his over his face and responds, "I know I went against everything my gut was telling me. But Sara told me that I needed to think what was the best decision for the case, I didn't want to risk anything that could interfere with solving this. You know I wanted to solve this case the first time we had it. For you and for Lindsey."

Catherine walks around the table and sits next to Mark and says, "This case got to all of us the first time. Hell I walked off in a huff at the crime scene because I didn't want to believe Eddie was dead. He'd been nothing but a bastard to me the whole time I knew him, but he gave me Lindsey."

Mark says, "I didn't mean to hurt you. I really want to close this one though, but if it's going to cause problems with us I'll walk away …"

Catherine cuts Mark off by putting her finger on his lips and insists, "Don't you ever say that. We're all a CSI first I know that."

Mark says, "But …"

Catherine interrupts him again, "No buts. You did what you had to do."

Mark asks, "Are we going to be ok though?"

Catherine says, "Let me ask you this. Is the PI still following me?"

Mark shakes his head.

Catherine says, "As long as we catch McKeen though I'll be safe. I don't know what deals he had with Eddie but if I know Eddie and I do, it's nothing good. I think the fact the Eddie was murdered with McKeen's gun proves that."

Mark looks at her surprisingly and says, "Seriously? I thought I had majorly fucked up here."

Catherine says, "I'm not entirely pleased with it but if you would have told me Sara was right it could have compromised the case."

Catherine leans forward and kisses Mark.

Mark separates from her resting his forehead on hers and says, "Uh oh you didn't check for anyone coming. We could have gotten yelled at for PDA."

Catherine says, "Sometimes it's worth the risk."

Mark is in the bathroom throwing some water on his face.

Brass comes out of a stall and says, "Ecklie and Grissom are on their way in. Are you going to be ok you've been on a really long time?"

Mark smiles and states, "I'll be ok once we find McKeen."

In Ecklie's office Mark, Brass, Sara, Catherine and Grissom wait for Ecklie to get off of the phone.

Ecklie hangs up his cell and says, "Ok Brass fill me in on this impromptu meeting."

Brass fills Ecklie and Grissom in on the situation.

Ecklie says, "Are you guys 100% sure because if we pursue this and we're wrong this will come down on us hard."

Grissom speaks up, "Conrad, I haven't been involved in any of the new investigation until now but I assure you that this meeting would not have been called if it wasn't proven with the evidence. We can't formally charge McKeen with anything, yet, but it does grant a conversation as to why the gun was not only used to murder two people but was tampered with."

Ecklie sighs and responds, "We need a way to bring him here without drawing suspicion. I'll see if I can set up a meeting and we'll do what we can. Until then you all are dismissed. Don't breathe a word of this to anyone outside of this group. I know for a fact that Anderson and Sidle are creeping into triple shift time in light of this new evidence, guys go home and sleep I'll keep you posted."

Mark is lying in bed when Catherine gets in bed next to him. He looks over at Catherine.

Catherine looks over with a questioning look and asks, "What?"

Mark replies, "Are you sure we're ok?"

Catherine rubbing lotion on her hands says, "Yeah. I thought we went over this?"

Mark sighs and responds, "Yeah but it just seems too easy."

Catherine laughs and says, "Honey not every relationship has to be complicated. And if you trying to protect me and solve a case is the worst you're going to do to me, we're going to be just fine."

Mark looks at Catherine and asks, "Do you think this thing with McKeen could get dangerous?"

Catherine replies, "I don't know about dangerous, but it's not going to be pretty. You think you are finally going to be able to get some sleep? This case is going to take a lot more energy I have a feeling."

Mark cuddles up next to Catherine and says, "I hope so."