"How the hell did Natalie get through the background checks?"

Gil glanced at Sara and saw her put down her veggie burger and swallow slowly. He worried that she was going to be sick, but she shook her head at him and gave him a weak smile as she sipped her water.

"She doesn't have a record, Gil," Catherine was saying, and he focused his attention back on the conversation. "Nothing came up in the checks because there wasn't anything to find-"

"Except she probably killed her sister when she was five," Sara muttered under her breath.

"What?" Catherine exclaimed. "Natalie Davis murdered her own sister! Is that true, Gil?"

He shot Sara a disapproving look before replying. "We don't have any evidence of that – we're still waiting on her file from family court. All we have to go on is hearsay and gossip from Ernie's son who overheard his parents talking about Natalie the night she arrived at their house-"

"Hmm, that won't hold up in court." Catherine paused and took a deep breath. "Judy is really upset about this whole thing – she wants to come down there and give a formal statement, work with a sketch artist – and apologize to you in person."

"She has nothing to apologize for – it's not her job to vet the janitorial staff."

Sara placed a hand on Gil's arm. "It will make her feel better and it will help to have an updated photo of Natalie," she whispered, her tone low enough not to be picked up on speakerphone. "Tell her to come by, Catherine," she spoke up. "We'll be here."

"I'm telling you for the third time now – I didn't send those cordials to my aunt."

"But you'd sent her the same candy in the past."

Mitch sighed and ran a hand through his wavy hair. "Yeah, but that was a couple of years ago! I told you, I'd sent her some for her birthday – but I'm not good at remembering dates or saying thank you for everything she did for me –"

Brass studied the young man sitting across the table from him. He didn't have the jitters, or any other symptoms of withdrawal, so his gut was telling him that Mitch didn't have a current drug habit. If he had been an addict in the past, in his youth, he had managed to kick the habit, probably with the help of his no nonsense aunt. His eyes were clear and focused, though a bit red from emotion when they had told him about his aunt's death. His hands were smooth – it was obvious that he had never worked a blue-collar job a day in his life.

"What do you do for work?"

"I have a degree in mechanical engineering from MIT – I work for Boeing in DC."

"Wow – sounds important. How'd you land a job like that?"

"Lots of hard work and perseverance. Look, I don't mean to be rude, but I've cooperated fully and if you don't mind, I'd really like to go home – well, to my aunt's home-"

"I'm afraid that's not going to be possible."

"Why not?"

"Because your aunt's house is a crime scene, and you are a person of interest in her murder."

Mitch's eyes hardened. "Then I want a lawyer."

Gil and Sara looked up as Brass opened and slammed his office door, shattering the quietness of their late lunch.

"Mitch lawyer-ed up."

Sara hid her smile behind her water bottle as Gil grunted. "I thought you were giving him the soft sell-"

"I was, but the kid wanted to leave, so I had to play it straight with him. He's on the phone with a public defender now-"

Sara interrupted. "We all know he didn't kill Alina."

Both men looked at Sara, waiting for her to continue.

"Natalie did."

Gil's left eyebrow quirked. "That's an interesting theory, but how do you explain the note?"

"Do you think Alina would have eaten chocolates from Natalie?"

Brass chuckled and Gil frowned.

"Why wouldn't she have just visited Alina and killed her – why frame her foster brother?" Gil shook his head. "It just doesn't add up – we're missing something-"

Sara snorted "We're missing a lot – she's still two steps ahead even though we know now she's been working at the lab-"

"What!" Brass exclaimed.

Sofia opened the door and poked her head in. "Great news! I found Natalie's biological father – Christopher Davis. He works at the regional headquarters for the US Doll Co. in Henderson. I'm headed over there now to talk to him – who wants to come along?"

Gil and Sara looked at each other, having a silent conversation before she slowly nodded. "You go, Gris. I'll stay and fill Brass in about Natalie and wait for Judy – she should be here soon."

He leaned over and took her hand, squeezing it softly. "You sure?"

She smiled. "Yes, but don't have too much fun in Henderson without me." She glanced at Sofia's retreating figure as the detective marched down the hall.

"Not a chance."

"So, you and Sara seem happy."

"Sofia-"

"What? Can't I offer my congratulations?"

"For what?"

Sofia stopped on the sidewalk outside the enormous skyscraper and turned to look at Gil, planting one hand on her hip. "You and Sara – you're together. Aren't you?" her eyes registered confusion as she looked at him.

He sighed. "I'm her supervisor, Sofia."

She narrowed her eyes before grinning. "So that's your story, huh?"

He pursed his lips before allowing them to curl upwards in reply. "And I'm sticking to it."

She laughed as they entered the lobby and after studying the roster for the building, they got on the elevator and pushed the button for the eighteenth floor.

The entire floor was leased for the US Doll Company and housed the offices and a large board room for the top-level executives of the western regional headquarters. There was a large reception desk manned with a woman who gave the appearance of a prison matron guarding inmates as soon as the elevator doors opened. She sniffed at their credentials but showed them to the office of Mr. Davis personally. She rapped on the door and opened it before the occupant had time to respond.

An older man in a three-piece suit, with dark hair liberally sprinkled with salt, looked up from his desk with a frown.

"Yes, Gerda, what is it?"

"Mr. Davis, I'm sorry to intrude, but these two are from the police."

He frowned and then relaxed. "Oh, I suppose it's about Mr. Fischer. You can leave us, Gerda. I'll buzz you when our guests are ready to leave."

Gerda's lips tightened to the point that her mouth almost disappeared. "Very good, Mr. Davis." She stepped aside to let Grissom and Sofia pass and then she left, slamming the door behind her.

Mr. Davis smiled. "Don't mind Gerda, it's her job to look intimidating. Please, call me Christopher. Now, how can I help you?"

Sofia flashed her badge. "I'm Detective Sofia Curtis, with the LVPD, and this is Gil Grissom with the crime lab."

The smile fell from Christopher's face. "Crime lab? Then you aren't here about Mr. Fischer – unless, has something happened to him?"

"Mr. Davis-"

"Christopher, please."

"Christopher, perhaps it would be better if you let us do the talking."

"All right." He motioned to the chairs in front of his desk, and they sat down, studying the man in front of them for a moment before Sofia continued.

"We don't know anything about a Mr. Fischer- we're here on a completely different matter-"

"Go on."

Gil spoke up. "We're here about your daughter."

Christopher went pale, and his left hand began to shake. "My daughter died over twenty years ago."

Sofia nodded. 'We know that your youngest daughter, Chloe, has been dead for years. We're not here -"

Gil interrupted her, his voice cutting through the tension. "We're here about your other daughter, Natalie."

Both of Christopher's hands were shaking now as he reached out to his phone and pressed a button.

Gerda's voice answered immediately, curt and cold: "Yes?"

"Hold all my calls and if anyone else comes to the office wanting to see me, tell them I am in conference and unavailable."

"Yes, Mr. Davis."

Christopher released the button and collapsed back in his chair. He opened a drawer in his desk and pulled out a small, framed photo, his fingers caressing the faces under the glass. "Natalie – I haven't said her name out loud in over twenty-five years. Not since the day Chloe died."

Sara was walking down the hallway, going back to interrogation after leaving the restroom when Judy suddenly stepped in front of her, a teary, hiccupping mess.

"Oh Sara! I'm so-" hiccup, "sorry!"

Sara placed her arm around the woman's shoulders and guided her down the hall towards Brass' office. "You don't have anything to apologize for – and you're not in trouble! It's not in your job description to run background checks on people that the lab employs –"

"But I feel-" hiccup, "so guilty! I should have-" hiccup, "seen that she was a criminal!"

Sara cocked her head to the side. "Why? Was she acting like one?"

Judy shook her head.

"Listen, Dr. Grissom and myself have been fooled many times by 'nice' people – but most of the time we catch onto them, or they trip themselves up and we arrest them. You can help us, Judy. The only picture we have of Natalie is from her childhood. You saw her many times – we need you to remember what she looks like now and work with a sketch artist, can you do that?"

"I'll do anything to help!"

"Good! Nick and Greg are also looking at the video surveillance from the hallways and by working together, I'm hoping that all of us will be able to put together a current photo of her. Is there anything else you remember about her – it may not seem important, but every little thing helps."

Judy shook her head. "I racked my brain on the way over here and the only thing I can think of is that Natalie hasn't been at work the past three days."

Sara dropped her arm from the other woman's shoulders. "Do you know why?"

"The cleaning service said she's out with the flu."

A cold knot of fear wrapped itself around Sara, but she managed a small smile for Judy. "That's helpful, thank you. I'm going to leave you here with Sam, he's an excellent sketch artist. I have some calls to make, and I'll be back to check on you later, all right?"

Judy nodded. "Thanks, Sara."

Sara backed away, keeping her expression neutral even though her insides were knotted up with anxiety.

What the hell are you planning, Natalie? And how much time do we have before you kill again?

"What exactly happened to Chloe?" Sofia asked, her voice soft, trying not to spook the emotionally wrecked man in front of them.

Christopher looked up, his eyes haunted with visions from the past, and his voice hoarse with pain. "Chloe was our miracle baby. After Natalie was born, the doctors said it was extremely unlikely that my wife would ever have another child – and if she did, it would be dangerous for both her and the baby." Christopher pushed away from the desk, and stood up to look out the window, keeping his back to Gil and Sofia. "But Caroline wanted another baby so badly and I was weak – I loved her so much. We waited almost two years – and then she got pregnant with Chloe – and things were going well. But she delivered a month early and they couldn't stop the bleeding and Caroline – she just slipped away. I was left alone with a two-and-a-half-year-old and a newborn."

Sofia fidgeted in her chair, impatient with the rambling tale, but Grissom shot her a warning look to be patient, that in time, Christopher would get to the point.

"I wouldn't have been able to cope without my family. First my brother, and then my sister took turns staying with us – helping out with the girls so that I could continue to work and put food on the table. Eventually, I was able to hire a couple of college kids to help out during the day and then come home to play with my girls and put them to bed at night."

"Do you happen to remember their names?" Gil asked softly and Christopher turned around in surprise, as if he had forgotten he was speaking to actual people.

"Why?"

"It would help our investigation."

For a long moment, it seemed that Christopher wasn't going to answer but then he replied, "They were brother and sister – fraternal twins. Riley and Jeffrey Addams – two d's."

"Thank you." Sofia wrote the names down in her notebook. "So, it seems that you had all the support you needed to raise the girls after your wife's death-"

Christopher winced. "I was coping with the situation the best I could, Detective. I missed my wife every single day and Chloe – she was the spitting image of her. It was like she was still with me. She helped ease my grief so much."

"And Natalie?"

"Natalie was always my quiet child – she had these eyes – not quite grey or green but a curious mix of both – sort of reminded me of a kaleidoscope. She would watch me, her sister, other people, with those eyes and you never knew what she was thinking. I swear if I'd known what she was thinking that day, I'd never have let Chloe anywhere her sister."

Sara called Platinum Cleaning first to check up on Natalie Davis. The manager was most upset to learn that her latest hire was a POI in an ongoing criminal investigation.

"You know, I should have known that girl was trouble. There was something about her that gave me the willies."

"Then why did you hire her?"

The woman huffed and puffed for a few seconds before admitting, "Because she had amazing observation skills! She described the reception area down to the minutest detail after only seeing it one time – after only sitting out there in it for fifteen minutes! She must have one of those photographic memories – what do you call them-"

A chill ran through Sara, like someone just walked over her grave. "Eidetic?"

"That's it! I can never remember the scientific name – you CSIs are so smart!"

Sara took a deep breath and internally counted to ten. "And you checked her references thoroughly? And ran a background check?"

"Ms. Sidle," the manager's voice was ice cold now. "We pride ourselves on our employees. I assure you this is the first and only time something of this nature has ever occurred. Natalie Davis's fingerprints came back clean. Her background and references checked out. I can send her report over to the LAPD if you'd like?"

"Please do – and if she contacts you again-"

"I'll let you know – just before I fire her."

The next call Sara made was to Greg.

"Hey girl! You ever coming back home?"

Sara smiled in spite of the serious situation they found themselves in. "Soon, Greggo. Have you found anything on the tapes?"

"Nope. Well, we've got a woman in a hoodie who we think is Natalie talking to Judy and then skulking around the hallways with a cleaning cart – but nothing we can run through facial rec. Sorry."

She sighed. "Let's hope that Judy's having more luck with the sketch artist."

She hung up and tried not to run down the hall to Brass' office. Judy saw her and eagerly waved her inside.

"All done?"

She nodded and held up a sketch. "This is her."

Sara took the paper and stared at the pencil drawing of a sad, tired, worn-out woman staring back at her.

"Hello, Natalie."

"Did Natalie kill her sister?"

Christopher rubbed a hand across his face. "I don't know – we were all right there, but no one actually saw what happened except for Natalie and she never talked about it. I always thought she did – and what kind of a father thinks that about his child? But the way she acted afterwards – I just – I didn't know what else to think."

"What happened that day?"

Christopher turned around to stare out the window once again. "It was Chloe's third birthday. The whole family was there, including Riley and Jeffrey, to celebrate. We had a picnic in the backyard with the girls' favorite foods, cupcakes, balloons, streamers – and presents for Chloe. When everything was winding down, I got a page from work. There was a problem at the processing plant – I wasn't an executive back then, just a supervisor on the line – and I had to go in. Both of the girls were in the treehouse – I know, Chloe was only three and shouldn't have been up there, but she was fearless, and she had been following her sister up there ever since she was two. I'd put in ladder steps and a safety rail around the top to keep the girls safe – I thought it would be enough – but it wasn't." He paused and cleared his throat, his voice becoming hoarse with emotion once again. "I called up to the girls, telling them good-bye and that I'd be back soon. Chloe was clutching her US doll, a present from me – she leaned over and blew me kisses crying, 'I love you, daddy!' and I blew kisses back saying, 'I love you, my angel'. I turned and walked down the drive but stopped when I heard a scream and a thud behind me. I remember my sister screaming Chloe's name as I turned around and saw her lying on the ground at the bottom of the treehouse, blood pooling out from under her head."

For a few minutes no one spoke and then Gil said softly. "Where was Natalie?"

Christopher turned around; his face etched with grief. "She was standing at the top of the treehouse ladder, looking down at her sister, just staring at her. She didn't say a word – not then - not for over a week. She didn't speak until the morning of Chloe's funeral-" he choked on a sob.

"What did she say?"

"'Chloe's dead, isn't she?'" he broke down completely then and cried for his lost little girl. "I know you think me heartless but I just – I just couldn't keep her with me. Every time I looked at her, I saw Chloe falling – her broken body at the base of that treehouse. I couldn't shake the feeling that she had pushed her sister to her death."

"And you didn't say anything to the police?" Gil pushed the issue.

"What good would that have done? It wouldn't have brought my angel back to me. And this was the 1980s – I wasn't going to have the cops throw my daughter in an institution for something that was a horrible, tragic accident."

"Except it wasn't."

"What?"

Gil's voice was hard, his tone accusing. "It wasn't an accident. It was cold-blooded murder, Natalie's first. You covered it up, ignoring your daughter's very serious and very early signs of delusional psychosis. This allowed her psychosis to grow unchecked and now she's a serial killer."

Christopher's legs buckled and he collapsed into his chair.

"Oh my God – what have I done?"

"You were a bit hard on him back there."

Gil and Sofia had exited the skyscraper and were once again on the sidewalk outside.

"He ignored the fact that his older daughter killed his younger for over twenty-five years, in large part because he favored Chloe over her. This whole case has revolved around parents and their children and how they have loved some more than others. I just hope that I'm-" he stopped suddenly, realizing what he was about to say.

"What?"

"Nothing. Look, I need some air –"

Sofia's radio crackled to life. "All officers in the vicinity of fifth and Sloane, please respond, we have a robbery in progress-"

Sofia looked at him. "That's just down the street."

He nodded. "Go. I'll take a walk down to Mama Casita's and get some takeout. You can pick me up there."

"You sure?"

"Go."

She radioed that she was responding and ran to her car, turned on the lights and floored it out of the lot.

Gil began walking as he pulled out his phone and dialed Sara.

"Hey – you get anything out of Natalie's father?"

"You were right – she killed her sister."

Sara sighed. "What happened?"

"I lost my temper."

"You hit him?"

He smiled. "No. But I went off on him. Told him that if he'd only reported Chloe's death to the cops, that he could have prevented all this – stopped Natalie from becoming a serial killer."

"That was a bit harsh-"

"I know."

"And you also know that it's not true – no one has a crystal ball and can predict the future. He was just looking out for his daughter."

"No, Sara, he wasn't! That's why I went off on him! He was only thinking about his precious Chloe – how much she looked like her mother – that he lost when she was born – and that he couldn't bear to be around Natalie without thinking of Chloe's death. He favored one child above another. This whole case has been like this – and I just – I just-"

"Take a breath, Gil. You're getting yourself all worked up."

He stopped and leaned against a building, resting in the shade. "I just – I can't help but think about you and me – and the fact that you might be carrying our child right now. I hope – if we are lucky enough to have more than one – I hope I never-"

"You won't."

"How do you know?"

"Because I know you. You have so much love inside that you've been saving up for me – and for our future kids. You're going to be a wonderful father, Gil Grissom. I never had any doubt about this, or I never would have let you try and knock me up."

"Sara!"

"Mission accomplished; I made you laugh! Now, try and relax. We don't know if I'm even pregnant with our first child – don't go borrowing trouble and be worrying about a second one yet."

His eyes fluttered shut as he imagined Sara there with him, wrapping her arms around him in comfort. "I love you."

"I love you too, you crazy man. Are you on the way back yet?"

"No, Sofia is responding to a robbery so I'm walking to Mama Casita's – thought I'd bring you back a treat-"

"Flan?"

"You got it."

He hung up and resumed walking, the weight temporarily lifted from his shoulders. He knew that he wouldn't have gone off on Christopher like that if Sara had been with him, but it wasn't feasible for them to be together twenty-four-seven. Besides, if she was pregnant, she would soon have to cut back her hours, and then be out of the field-

"Dr. Grissom?"

He turned to see a young woman in a hoodie standing quite close behind him, and he squinted in the bright sunlight, trying to focus on her face.

"Yes?"

"I've been looking for you."

"Excuse me, but do I know you?"

"Not yet-"

Natalie raised her arm and the taser beam hit Grissom's shoulder, the pain hitting him hard as he collapsed on the sidewalk, writhing in agony. She moved quickly, picking him up under the shoulders and putting him in the trunk of her car parked at the curb. She leaned down just before she shut the lid, murmuring in his ear:

"But I promise we'll have some time to get to know each other before you die."