A/N: If you want to avoid Avengers: Endgame spoilers, please skip this story.

Richard Castle knew that It wasn't about the story, any more. The story had ended badly. Well, not ended. It was an ongoing nightmare. There was a time when he might have ended it himself - but the effort seemed too great, the act too cowardly.

Castle had started writing about it, but gave it up, as for a long time he had no idea why or how it had happened. After he found out about - well, he still had no idea why or how, just what - he had started writing a new story, with a happy ending, but he ran out of hope and abandoned it.

Hope. There was the ultimate irony. He still had Hope.

She had been named Lily, for a couple of weeks. A beautiful baby with a beautiful mother. Loved by an exuberant grandmother, an amazing half-sister. And himself. He almost hated his own capacity for love - it had turned into so much pain, in the blink of an eye.

They were walking down the hallway toward the loft, Castle toting the sleeping baby in her carrier. They were coming back from Lily's first visit to the precinct and all three of them were weary; he was sure a family nap was about to be had. He opened the loft door and set the carrier down quietly, turned to say something to Kate -

No Kate. No sign of her, though in hindsight he realized the dust whispering down the hall must have been part of the - event.

No Alexis, though he called and searched and roamed the city looking for her. Martha remained, bitter, wishing she had been the one to vanish. Not her beautiful granddaughter.

So he renamed the baby Hope, in some desperate attempt to remind himself that there was still a chance that happiness, or simply acceptance, would come some day.

He'd been too busy, and too frantic, in the first days to turn to his usual forms of self-medication. Alcohol, horror films, parties, exhausting himself just to be able to sleep. But nothing mattered more to him than keeping her alive, keeping his eyes on her every moment of every day, terrified that she might vanish like the others.

It seemed, however, that the damage had been done all at once.

The great loss of human life had taken a practical toll along with the emotional and social fallout. There were fewer people to maintain the workings of the city itself, fewer hands to care for the sick, run the subway, keep the power plants and phone lines running. Life went on, but it took more effort; Castle had never really understood how dependent he was on the continuity of life until it vanished along with half of humanity.

People re-learned how to help each other, share their goods and homes and skills and sorrows with those who were left. Castle didn't have anything to offer except compassion, and a lot of money, so he left most of the money in a fund for those who had lost support and decamped to another island.

He took his precious daughter to live in the Hamptons, where he learned to plant a vegetable garden, set up a sustainable water supply, bartered with neighbors for clothing and child care. He was glad he'd adopted solar energy for the house a couple of years before the - disappearances.

It was the only home Hope knew. She was nearly five years old and happy, and Castle intended to keep her that way as long as possible.

One night he was reading to her on the sofa in front of the fire when his cell phone rang, from its place on the side table. He ignored it; it could wait until the story was done and Hope was in bed.

"So when she saw what - "

"Daddy. Who's Beck - Beck - It?"

Blindsided, Castle gaped.

"What did you say?"

She pointed to where her sharp eyes had discerned the name on the face of the phone as it lay face up on the table.

"Beck - itt?"

Castle dropped the book, leaned across the child on his lap, and picked up the phone. The sight of her face on the screen hit him even harder than the name.

"Castle," he answered gruffly.

"Rick." It was a voice filled with desperation, fear, longing. "Rick, where are you?"

"Who is this," he demanded.

"What? It's me, it's - it's Kate."

"This is a sick joke," he growled. "Who the hell is this?"

"Daddy," said Hope.

The woman on the phone gasped.

"Oh, my God, Is that - Is Lily - "

"Her name is Hope," Castle snapped. "Leave us alone."

He ended the call and turned off the phone.

That night he lay awake in bed, with his daughter in her little bed in the corner. (The house was big enough for more than the two of them, but he'd awakened in a cold sweat so many times, rushing to check that she was still with him, that it seemed more practical for them to sleep in the same room, at least for now.)

As far as he knew, Beckett's cell phone had been tucked away in his desk when he left the loft. He'd let his mother and some of her students live there rent-free on the condition that they stay out of his office. Someone must have wandered in and found her phone. He would try caliing Esposito tomorrow, see if everything was all right in his old home.

The Twelfth Precinct still had plenty to do, with fewer forces to protect and serve, but Castle knew that the boys would do him this small favor.

In the morning, he put on his usual brave face, made smiley pancakes for Hope, and walked her the few blocks to preschool. It wasn't right for her to be shut up with her hermit of a father all the time, and he knew there were things he couldn't teach her himself. As usual, he'd brought a book, and he settled in at an outdoor table at the cafe across the street.

He'd barely finished the first chapter of Naked In Death (which he'd read a hundred times anyway) when a familiar voice hailed him.

"Hey, Castle. Crazy day, huh?"

He looked over to see the police chief, Brady, leaning out of the window of his patrol car.

"Not any crazier than usual," Castle replied. He got up and went over to the car. "What's going on?"

"You haven't been out and about long, have you? Noticed anything different?"

"No, to both questions," said Castle impatiently. His taste for mysterious conversations had faded somewhat in the last few years. "Just dropped Hope off at school. Anything I should be worried about?"

"I don't think so," said Brady. He seemed hesitant, as though reluctant to bring up a painful subject. "Have you had any - strange phone calls, lately?"

Castle's eyes widened. Brady nodded.

"You have. I can tell. So did I, last night. And this morning - well, if I were you I'd get home. Someone might need to find you."

The car pulled away, leaving Castle staring after it. He shook himself and turned slowly to scan the area, seeing nothing out of the ordinary. Then again, apart from summertime, this part of the island was fairly quiet; no tourists, no holiday weekends, no day trippers. He sat down again with his book and made himself wait through the three hours before he could pick up Hope.

To see her running to him, her eyes shining, hair flying, to feel her little arms around his neck - this was what he lived for. In time he might be able to handle being back in the world again - would need to be, for her sake - but for now she was his world.

"Come on, bug," he said, swinging her up onto his back. "Today you can have a ride. And ice cream when we get home."

"What happened, Daddy? Were you extra good today?"

"Not really," he admitted, "but the day isn't over yet. We can be extra good together."

"After the ice cream."

"Right."

Alexis would never approve, he thought, not without a pang. She'd been the child who had set her own limits and rewards; she'd insisted on earning the ice cream first. Castle reminded himself that he was blessed to have even one survivor in his family...

...then he saw the car in front of the house and stopped dead in his tracks.

"What, Daddy?" Hope craned her neck to look around his head. "Who is it?"

He didn't recognize the car; it couldn't be anyone they knew in the Hamptons.

"I don't know, honey," he said. "I think you should get down now."

He'd seen that his front door was open.

"We're gonna play sneakers now," he said quietly to his daughter. "Remember how? You sneak along behind me, like Little Bear in Blueberries For Sal. But don't get lost, okay?"

"Okay, Daddy."

Castle moved slowly up the walk, hearing Hope's light steps behind him, and stopped in the doorway. He looked inside, left, right, up the stairs, seeing nothing out of place, then decided he'd go around the back. He took Hope's hand and gestured for silence; she nodded and crept along quietly with him.

When they reached the back lawn and were about to step up on the patio, Castle heard a voice from inside the house.

"Rick? Rick, are you here?"

It was the voice he'd heard on the phone. The voice he never thought he'd hear again. Calling his name.

"Oh, God, he has to be here...Rick! Rick? Castle?"

There were footsteps pattering downstairs, getting closer. Castle made Hope squat down behind a patio chair, out of sight of the doorway, just as the French doors swung open to reveal the woman who'd been calling.

The woman who -

The woman who had - who was -

"Kate," he whispered, just before the world spun and he found himself on his knees in the grass.

"Daddy!"

He was still staring up at his wife when his daughter barreled into him, knocking him on his back, her arms tight around him.

"Daddy, Daddy! Are you okay? Wake up Daddy!"

She was patting his face, looking anxiously into his eyes. Another face appeared beside hers, looking down at him, not anxiously, but tearful all the same.

"Rick," said Kate. "You're alive. I'm alive. Oh, God, what happened?"

"He fell down," said Hope. "Come on, Daddy, get up."

She grabbed one of his arms and Castle sat up, immediately pulling her against his side, still staring at Kate. Then he reached out to grasp her wrist tightly, muttering, "Real. You're real. Not dreaming - not this time."

A smile glimmered through her tears. "Not dreaming."

"Daddy, are you okay?" Hope was less interested in their visitor than in her father's sudden lapse. He smiled down at her.

"I'm better than ever, bug," he said. "Better than I've been for five years."

"Five years," Kate echoed. "I didn't believe it, at first. Five years!"

"I'm five," said Hope. "I mean, I'll be five. In July."

"What's your name?" Kate sat down on the lawn beside Castle.

"Hope. Hope Castle," said the little girl. "What's yours?"

"Kate," said the lady. "Kate Beckett. I mean, Kate Castle."

They'd just been discussing whether she wanted to change her name, just before the baby was born, Castle remembered.

"But you should call her Mommy," he said suddenly, and just as suddenly lunged over to scoop his wife into his other arm.

They didn't try to explain to Hope why and where Mommy had been away, how she got here, not that they understood much of that anyway. She went down for a nap after lunch and some stories, having been promised a game of Candyland before dinner, and Castle came downstairs to find Kate gazing raptly at the pictures on the wall. Pictures of her husband, her daughter, Alexis, herself. Her family.

He went to lay his hand on her shoulder, approaching cautiously as if to keep from startling her, and she turned into his arms, held him tight.

"What happened? How did you - where did you - ?" he whispered, the questions spilling out at last. Kate drew back to look at him.

"I don't know if I went anywhere," she told him. "We were walking down the hallway - you had Lily in the carrier and you went to unlock the door."

"When I turned, you were gone," he said. "Just - gone. I thought - I don't remember what I thought. I left the baby asleep in the carrier in the living room, left the door open, ran up and down stairs calling for you. Tried to call the lobby - No answer. Eduardo was gone, too."

He sat down heavily on the sofa, Kate beside him.

"Steve Rogers - he made a public service announcement - there was an incident, a battle somewhere in Africa, and something that happened there made half the living creatures on Earth disappear. Randomly. It didn't seem to matter if they were a certain age, or gender, or species, or... Smarter people than me are still trying to figure it out.

"There was panic, sheer panic, in the city," he went on. "I had lost you, and I didn't know who else might be missing. But I had Hope - I mean, the baby - and I had to keep her safe. The phone lines were so jammed, I could hardly get hold of anyone, anywhere. Paris, Budapest, California - Meredith didn't answer, nor Gina. Later I found out that Gina survived. And your dad. Have you seen your dad?"

"I have," said Kate. "That's his car. When I - came back, there were people in the loft, and they said they were allowed to live there, and some of them knew Martha - and I called you, on my phone."

"And I hung up on you," said Castle.

"I don't blame you for it. I called my dad then, and went to his place, called the precinct this morning - Espo told me where you were and I came straight here." She held his hands and asked, "What about Martha? And Alexis?"

"Mother passed away three years ago," said Castle. "Heart attack. She was living in the loft, with her students, and they couldn't revive her. They said she was rehearsing for a new version of King Lear - the one Glenda Jackson took over - "

"I'm so sorry, Rick."

"Alexis - I don't know what happened to Alexis," he went on. His throat tightened. "I couldn't find her at the college, or any of her friends. I kept looking, calling, but - people scattered, they went back to their families, or away from the city. Espo and Kevin said they'd keep looking. I had to escape, raise Hope somewhere else. Here."

"You're obviously doing a great job," said Kate.

"Not as great without you," said Rick.

He was just pulling her in for a kiss when the cell phone chimed. This time he snatched it up without even looking at the caller ID.

"Castle."

"Daddy? It's me," said Alexis. "Where are you?"

~fin~