Mark is researching paint that was found on his and Sara's crime scene.

Sara walks in frustrated and says, "I'm not sure coming out was the best decision."

Mark looking up from the computer asks, "Why's that?"

Sara sighs and replies, "Well for starters the line I seem to be getting from everyone is 'Someone I know is gay, you two should go out.'"

Mark chuckles and says, "Yes, because all gay people immediately want to date each other."

Sara smiles and says, "Exactly! So what are you finding out about this paint?"

Mark sighs and responds, "Just that you can find it just about anywhere. It's basic flat wall paint, nothing special. So we could be looking for someone that is painter, or perhaps the victim just painted recently, or either the suspect or the victim stepped in paint recently. I'm not seeing this being much of a lead to anywhere. I will double check the victim's recent purchases and see if maybe they recently bought the paint."

Nick comes in and says, "Hey guys I may have a link between our cases. We found that exact same paint at our crime scene. Is there anything special about it?"

Mark looks at the report Nick hands him and says, "Actually no it's pretty common. So we'd probably need a stronger link between the scenes."

Nick asks, "What lead were you two going to check out next?"

Mark replies, "I was going to check the victim's recent purchases and see if anything pops up." Mark turns to Sara and asks, "Has anything we sent to DNA panned out?"

Sara says, "Not yet but they are pretty backed up. Even though Warrick is helping Wendy, I feel like he's slowing things down since he doesn't prep and run samples that often."

About an hour later …

Mark looking up from his computer says, "Hey Sar I found something interesting. I traced recent credit card purchases and found that the card was used at a hardware store the day after the victim died."

Sara asks, "What hardware store?"

Mark replies, "Ace Hardware. It's lists a store number on the credit card statement but I don't see a way to look up store numbers on their website. I see 4 listed in Vegas, 1 listed in Henderson and 1 listed in Boulder City locally."

Sara says, "If the suspect is the purchaser maybe we can get security footage."

Mark takes out his phone and dials Brass and says, "I'll see what Brass has to say." A few seconds later Mark says, "Hey Brass its Mark. I'm running a list of recent purchases from the case Sara and I are working on and I found a local Ace Hardware store number on the statement, but I don't have a way to cross reference the number, can you help us out?"

Brass says, "Yeah I can do that for you. Are you thinking the suspect purchased something at Ace?"

Mark says, "We found a fairly common paint at the crime scene which seemed like a dead end but I decided to see if the victim had recently purchased paint. I looked at the recent credit card purchases and saw Ace listed a day after Doc Robbins estimated the TOD."

Brass says, "Ok I'll see what I can find out. Maybe they have security footage. Can you email me a copy of the statement?"

Mark says, "Doing that as we speak you should have it momentarily." Mark ends the call.

Sara asks, "Do you think this is related to Nick's homicide now?"

Mark replies, "It's possible. We should go back to the scene. Even though the body was a few days old I never thought to think that maybe the crime scene had been painted. But it would be consistent with not finding blood on the walls."

Sara nods and says, "True we assumed at the time that the victim had lost all the blood on the floor. But if that were true there wouldn't be a need to paint. We should check out the walls and see what we can find."

At the crime scene …

Mark and Sara take out their black lights and start going over all of the walls in the house.

They have been at it for hours and have come up with a big fat nothing.

Mark says, "Damn I really thought we were going to get somewhere with this lead!"

Sara leans against a wall in the kitchen and says, "Yeah me too but …" Sara stops as she feels an inconsistency in the wall behind her. She turns around running her hand against the wall. She asks, "Hey Mark does this wall feel odd to you?"

Mark comes over and feels the wall. He says, "Yeah it does. I can't figure out why though." Mark feels another part of the wall in the kitchen and it definitely has a different texture. Not enough that it would be seen but enough that it can be felt. Mark says, "Sara I think something is behind this. Do you have any hammers or a crowbar in your SUV?"

Sara says, "I should have something I'll be right back."

Mark cell goes off and he answers, "Anderson."

"Mark it's Brass," says the voice on the line.

Mark asks, "Hey any leads with the Ace purchase?"

Brass replies, "Yeah but more than paint was purchased. I have a sample of the paint purchased with the credit card and will give it to Hodges for comparison. Anyway drywall was also purchased along with some other small things."

Mark says, "Funny you should mention that Sara and I just found a wall in the kitchen and the texture doesn't match the rest. She went out to get a tool because we think something might be behind it."

Brass says, "Sounds like probable cause to me. Let me know what you find."

Mark says, "Sure thing." As he hangs up the phone Sara walks in and he says, "Hey I was just on the phone with Brass and apparently a drywall purchase was made with that credit card at Ace."

Sara handing Mark a tool says, "Nice hopefully this leads us somewhere."

Once part of the drywall is removed there appears to be a basement door. Once the drywall is removed Sara opens the door. Mark draws his gun and flashlight and enters first.

Descending down the stairs Mark asks, "Smell that?"

Sara replies, "Yeah definitely a copper smell, could be the original crime scene."

As they reach the bottom of the stairs Mark points his flash light toward the floor stepping lightly making sure not to compromise evidence. Mark finds a pool of blood to the left of the stairs and says, "Sara I've got blood."

Sara who went to the right responds, "Me too."

After the scene is photographed and blood evidence is collected they head back to the lab and give the DNA samples to Warrick and Wendy for analysis.

Sara and Mark are in the break room discussing various things and Mark mentions the screened in patio he wants to add to the back of Catherine's house.

Sara says, "Hey let me know if you need help. Through summers in college I made a lot of extra money working construction."

Mark intrigued says, "Really? That's cool I'll let Cath know. If the 3 of us do it together it probably wouldn't take any time at all."

Sara says, "We could probably get it done in a day. The electric run might have to be done another day, but the structure could definitely get done in a day. But of course staining or painting will probably be another day as well right there."

Catherine walks in and asks, "Hey guys how's your case?"

Sara replies, "It was really dull until I discovered the secret door!"

Mark sarcastically says, "You're going to brag about that door forever aren't you!"

Sara pretends to brush off her shoulders and says, "I'm just that awesome. You know you wanna be like me!"

Catherine laughs and asks, "What kind of secret door?"

Mark replies, "A basement door covered up with drywall purchased at a hardware store with the victim's credit card the day after the murder or murders depending if the blood we found also belongs to Nick's victim. There were two pools in the basement."

Sara says, "So Cath Mark told me about his screened in patio idea on the back of your house. I offered my services up. I made a lot of extra money during the summers in college working construction."

Catherine sitting down next to Sara with a cup of coffee says, "Really? I didn't know that about you."

Sara nods and says, "Yeah I haven't thought about it in years." Sara stares off and smiles at a memory, this is something that does not go unnoticed by Mark and Catherine.

Catherine asks, "What's that smile about?"

Sara blushes.

Catherine chuckles and says, "Oh it must be good. Do tell."

Sara says, "The first summer I worked construction I had my first serious girlfriend, Jackie. One of those first loves that you stupidly think is going to last forever."

Mark smiles and responds, "Yeah I think we've all been there."

Catherine asks, "So what happened?"

Sara responds, "After the summer was up she went back to where she was from. She was just visiting for the job we were working on. One of those things you say you are going to keep in touch, and we did for a while, but eventually we both stopped. I think we realized that we were both on different paths." Sara looks at Catherine expectantly for her first love story.

Catherine takes a sip of coffee and says, "I was 17 and his name was Tommy. He worked at the movie theatre. We spent most of the summer making out in the back of the theatre when he was supposed to be working. I remember wearing his class ring and a little into our senior year he moved away and we never spoke again."

Catherine and Sara both look expectantly at Mark awaiting his story.

He smiles and says, "Her name was Andie. It had its moments. I thought this was it; we were going to be together forever. Then we broke up 2 or 3 times. She had this other guy on the back burner. Long story short she married the guy and sent me an invitation. I was devastated. But looking back on it now it wasn't a relationship as much as two people having a ridiculous amount of sex."

Catherine said, "Wow. She sent you a wedding invitation, that's a bitch move. Please tell me you didn't go."

Mark laughs and responds, "No I didn't. We've talked since though. They are still married, happily as far as I know. We both apologized. There were so many things that we both did wrong; I don't even remember them all at this point. We both grew up. We email every once in a while."

Catherine asks, "Was that the relationship that you and Kerri bonded over?"

Mark nods and replies, "That was the initial one anyways. There were more beyond that."

Catherine looks at Mark and smiles. He had opened up about one of his relationships that had to be progress.