Katherine rushed out of her car and ran through the rain to the brick building, a newspaper over her head. A man in a raincoat was just opening the front door of the building. He held it open for her and smiled as Katherine hurried briskly through the door into the entrance hall. She was grateful, not only because the man didn't ask any questions, but she hadn't been sure if the person she was here to see would even let her in.

She stuffed her soggy newspaper into a trash can next to the entrance, shook her hands dry, and tried hard not to think about the last time she had climbed the two floors. But when she finally stood in front of apartment 3A and put her hand to the brass knocker, she was overcome with emotion, and she froze for a moment as if trapped in a recurring nightmare from which there was no escape.

A violent clap of thunder made the building tremble, reminding Katherine of one of the blackest days many, many years ago when she was still a bloody rookie. But this time, she would act before it was too late. Pushing her feelings aside, she grabbed the knocker and slammed it twice against the wood. No sooner had she let go than footsteps approached. But they were not the ones she had expected. They were quieter, lighter.

More feminine.

She heard the cover of the peephole being pushed aside, then a sharp intake of breath from behind the door. As the lock was unlocked almost frantically, Katherine expected to see before her the frightened little girl she had met years ago, perhaps a little older now.

But then, to Katherine's surprise, a beautiful, smiling teenager stood before her. A young woman with silky brunette hair and piercing blue eyes that she had no question inherited from her mother. Those eyes were moist and large now, looking at Katherine, the long-lost family member. "Kate," the girl said, recognizably thrilled to see her, and wrapped her arms around Katherine.

She heard the name through the door and sat up in the bed where she spent far too much time in, as she well knew. She turned her head to look at the clock on the nightstand, but she didn't see it, and she realized she had her head buried between the pillows. When she heard the name, at first she thought she was dreaming. But the conversation out there finally convinced her that she was very much awake. She jumped out of bed, went to her closet, and put on a shirt and sweatpants.

"My God, Nikki, you've really grown up," was all Katherine could get out as she returned the hug, suddenly feeling her nervousness about her visit dissipate.

"Come in before the dog gets away."

Katherine stepped inside and looked around. It had been some time since her last visit; all she remembered was that the apartment, while not dirty, had been very messy and full. Now she saw the freshly painted ice-blue wall in the hallway, with family photos hanging on it. A new, virginal-looking brown leather couch in the living room, and armchairs facing a flat-screen TV that Katherine estimated had to be at least sixty inches. But she also noticed a more feminine touch. A vase of high-quality artificial forsythia stood on a round cherry wood table. And everything was fastidiously clean and neat. It took Katherine a moment to realize that the woman who had brought this about was not a new family member, but the smiling teenager standing before her.

"How are you?" asked Nikki. "Or rather, where have you been?"

Katherine was surprised by the question and instantly decided to tell Nikki nothing but the truth. "I've been taking some time off," she admitted. And then she wondered why the girl had asked. "Have you tried to contact me?"

Nikki nodded slowly. "Several times. The last time was about six months ago. I called the hospital in New York, but they said you weren't there anymore." Katherine felt bad that she hadn't been there to take Nikki's call. "It wasn't that important; I just wanted to ask you something," Nikki continued as if she had read Katherine's mind.

Katherine was about to answer when the clink of a dog collar alerted her to a friendly German shepherd approaching to sniff her. "I don't even remember you guys having a dog."

"His name is Max," Nikki explained. "He helps Ma get along."

Katherine nodded. She'd been afraid it would come to this. "Then Max is -"

"A kind of therapy dog," the teenager confirmed.

"I see."

"Well, Max is responsible for that monster TV."

"It's really big," Katherine confirmed with a slight frown, thinking that Nikki neither spoke nor acted like a teenager. "How's Ashlyn doing?" she inquired of Nikki's younger sister.

"It's slowly getting better. She took Grandma's death really hard -" Nikki broke off when she saw Katherine's shocked face. "You didn't know, did you?"

"When did this happen?" asked Katherine, slapping herself even harder inside for not staying in touch and not knowing that Sarah's mother had died.

"You didn't know," repeated Nikki, who now realized that her mother and Katherine hadn't spoken in months.

"I should have known," Katherine stammered. "Your mother and I ... we haven't seen each other in a while. I'm so sorry."

"Thank you," Nikki said, sounding a little too much like the adult she was far from being. "She passed away about five months ago." She looked her aunt in the eye. "Grandma had pains in her stomach, and she was declining mentally. By the time Ma finally convinced her to go to the doctor, it was too late. She had terminal pancreatic cancer."

"Three weeks later, she was dead," a familiar female voice rang out from the hallway where Elizabeth Rizzoli emerged, dressed comfortably in sweatpants and a Boston Celtics shirt. There was no denying that she was Jane's daughter. However, she was slightly shorter and had lighter eyes and hair that wasn't as curly as Jane's. Her serious expression softened when she came into the living room.

"Liz," Katherine said with a faint smile.

"Kate," Elizabeth replied, almost seeming glad to see her little sister again. "To what do we owe this delightful as well as surprising visit?"

Katherine was unaware that she was smiling until she remembered what they had just been talking about and changed her tone. "I'm really sorry about Leonor."

"Thank you," Elizabeth replied. "At least it was quick. We took her straight to hospice, they drugged her 24/7 with morphine, and she didn't feel a thing."

"That's good," the younger woman said, then qualified. "If such a thing can be good at all." What am I talking here, she thought. She had played out this scene a dozen times on the way over, wondering what it would feel like to see her sister again, who had not only saved her life once but had helped bring closure to those horrible childhood experiences that shaped her. She owed Elizabeth much, if not to say everything. She had been convinced Elizabeth would treat her with indifference since she had simply disappeared without explanation. But now as she stood before her sister, she saw that Elizabeth was grinning, which she had not expected.

Elizabeth still looked as good as she remembered, a few more wrinkles in the corners of her eyes. Nothing had changed in her lean, muscular figure. She apparently still went to the gym every day.

Elizabeth seemed to sense her little sister's discomfort and turned to her daughter to resolve the situation. "Finished your homework yet?"

"School's pretty much over, Ma," Nikki said, speaking for the first time like the teenager she was, in that 'are you dumb or what' tone teenagers used to talk to their parents. But she understood what her mother was trying to say. "I'll leave you two alone for a while," she said, smiling at her aunt. "Don't let her get you in trouble."

"I won't," Katherine replied, turning back to Elizabeth. "Your daughter is all grown up."

"They both are, and much more quickly than I would have liked," Elizabeth replied, leading her sister into the living room, where she dropped into a comfortable brown leather chair that matched the new couch well. Her face was slightly tilted toward the window.

Katherine assumed she was watching the raindrops on the window.

After a while, Elizabeth spoke, "The girls loved their grandmother. In spite of everything, she took good care of them. And then she died so quickly that they barely had time to say goodbye."

"They take a developmental step to fill the void," Katherine said, "It's normal after losing a parent. Fortunately, they have a strong mother."

"A mother who would rather hole up in her work.

"You do what you can," Katherine replied, suppressing the need to go to her sister and trying hard not to sound like a psychiatrist. "Sarah's death was not your fault."

When Elizabeth looked at her, there was a bittersweet smile on her lips. "Nikki is the new mom in the house. For Ash, and sadly, for me."

"That's not your fault either."

"I thought about you a lot when all this was happening."

Katherine tried not to let on how frightened she was that her sister would actually say such a thing. She knew Elizabeth wasn't known as a fountain of emotion. "Nikki said she tried to call me. I'm sorry I wasn't there for her. I wish I could have helped."

Elizabeth shrugged as a sign that it was okay. "You had to mind your own business. I thought I could handle mine. Without a shrink," she repeated the old joke between them both. "And Mom helped me a lot too."

Katherine smiled, feeling sorry for her sister and hoping she didn't show it. Now I understand. Ma stood by me during my hard times, and Mom stood by Elizabeth. It was a division of labor of sorts.

Elizabeth looked up at her sister. "Are you actually going to stand there? Because I'm starting to get an inferiority complex. It's like Freud himself is hovering over me."

Katherine hadn't noticed how motionless she had remained. "You're right about that, though. Freud wouldn't have liked the way I tower over you." She sat down on the new couch, whose cushions were a touch firmer than she liked.

She slid around, and her apparent discomfort reminded Elizabeth that she hadn't asked her a single question yet. "You haven't told me how you're doing," she observed.

"Better," Katherine replied.

"So, once again, the psychiatrist doesn't want to get on the couch herself."

Touché, Katherine thought. "That moment ... With the gun ... I think it's in one of the nightmares I keep having."

"You think?" asked Elizabeth, raising her eyebrows. "What do you mean?"

"I don't remember the details very well. Of the nightmares, I mean." It was more than Katherine had wanted to relate. But somehow she felt more at ease in Elizabeth's presence than she had in months. She sank relaxed against the back of the sofa, wondering why she suddenly felt almost at home.

"You know there's nothing to be afraid of anymore," the detective tried to convince her, looking at her as if she were interrogating a suspect.

"I wish it were that simple. This feeling, the fear, lasts even when I'm already awake."

"But those dreams aren't the only thing scaring you right now," Elizabeth said, standing up as if she had convinced herself she could read Katherine's mind.

Katherine shifted her weight again, not knowing how to bring up the reason for her visit and fearing Elizabeth might guess what she was thinking. And that's exactly what her sister apparently did.

"Whatever you need my help with, you don't have to be afraid to ask," Elizabeth said now. "So go ahead, ask."

How the hell do Ma and her always know what I'm thinking? Katherine cleared her throat. "I don't want to take advantage of -" That was all she could get out before Elizabeth interrupted her.

"Ask," the detective commanded.

Katherine nodded and related what had happened to Rosa Castillo that morning. She spoke for ten minutes, with Elizabeth interjecting only an occasional question.

When she had finished, Elizabeth summed up the situation. "You think the guy who handcuffed her was impersonating a cop."

"I checked everywhere," Katherine explained. "If she was arrested, she should have shown up somewhere by now. The fact that the guy used Rosa's cell phone to call her mother says it all for me."

"I would think so, though," Elizabeth agreed with her sister. The cogs in her head began to work.

"Could it help if you called Missing Persons?" asked Katherine.

Elizabeth headed toward the kitchen and her sister followed. She turned on the modern coffee maker and took two cups from a wall cabinet. "The problem is that they don't assume adults are missing until forty-eight hours later," she said with a frown that eerily resembled Jane's. "And not even me or Ma could make the machinery run faster. They get calls like this all the time, and overworked as they are, they're not going to take on another case just because we say so."

Katherine also frowned as she sat down at the kitchen island. "Is there a unit that deals with kidnappings?"

"Major Crimes Division," the detective said, leaning her hip against the kitchen island and crossing her arms in front of her chest. "But they need proof that there actually was a kidnapping, and I don't think you have one. And even then, they only take action when they get the go from their department head."

Katherine was beginning to think that solved the problem. "You work for Ma -"

"If I went to her with this, or if she gets scent that I was involved, she'd hang me like a chicken in a Chinese restaurant."

As much as she wanted to find Rosa, Katherine couldn't do it at the expense of Elizabeth's job. "What about locating Rosa's cell phone?" she suggested. "At least then we'd know where she'd been for the last twelve hours."

Elizabeth looked thoughtfully at the kitchen ceiling as if it were a possibility. "Without a court order, it's very difficult."

"She's on probation, and the man on the phone said she left the state. Doesn't that make her a fugitive?"

Her sister nodded in agreement. "But the probation department would have to declare her a fugitive, and the court order would have to go through them."

That was exactly what Katherine didn't want to hear. "When the probation department comes into play, the whole thing is out of my control. She's a victim, not a perpetrator."

Elizabeth filled the two cups with coffee and slid one of them across the kitchen island, again frowning deeply. "Until you can prove that, no judge is going to let us dig into anyone's phone records."

"Okay," Katherine said, not giving up so easily. "You say it's hard to do it without an order. So it's not impossible, then, is it?"

She tried to bait her, but Elizabeth didn't bite. "It's not as easy as it looks on TV, Kate," she replied seriously. "And please excuse my selfishness, but it's my ass that's at stake here. If I arrange it without Rosa's approval, I'm breaking the law. Not only would I be fired, but I would also lose my pension benefits and possibly go to jail. And we won't be able to get Rosa's consent, right?"

Her jaw muscles twitched in agitation. And then Katherine realized why. Elizabeth wanted to help her. Her willingness gave Katherine a thought. "Does permission have to come from the person using the cell phone, or even the person in whose name it's registered?"

Elizabeth lowered her cup and furrowed her brows. "Legally tricky, you can ask Mom. But is that the case here?"

"I don't know. But I know her mother. And I doubt a cell phone company would sign a contract with a woman convicted of depositing a bad check. Do you?"

"I'm sure they wouldn't," the older woman sighed. "And that's why we spend so much time trying to get data on cell phones without contracts."

Katherine had counted on that. "But that option wasn't available to Rosa because she would have had new numbers all the time. I made it a condition of her release from prison that she get a normal cell phone and be reachable day and night. I was more concerned about Rosa's safety than being able to monitor her. I bet Rosa's mother has two cell phones registered in her name, and one of them is Rosa's. And her mother would do anything for me."

Elizabeth looked at her sister with her piercing brown eyes. "Even with her mother's permission, it's a huge risk if we get caught."

Even though it sounded like a warning, Katherine saw that it was little more than a hedge against all eventualities. Elizabeth was on board. Determined. Hungry for the solution. "If Rosa was taken," she said, "it's worth the risk, isn't it?"

Elizabeth considered. She hadn't taken a risk in a while. And if her sister was right, someone out there was in big trouble. "I'm not promising anything," she replied. "And if someone starts snooping around, I might have to stop. But I'll give it a shot. How does that sound?"

Katherine stood up. The Elizabeth Rizzoli she knew, the one who wouldn't take no for an answer, was back.

"It's more than I could ask for," she said, hugging her big sister. "Thank you."