She should stay there until five-thirty—they all should—but it's a gorgeous day. Spring has finally come to New York, and it's all the more welcome after the brutal winter. Finally Gates tires of all the longing looks her detectives keep throwing at the windows and the greenery and warmth outside; with a curt nod and a "well, just this once" expression, she gives them permission to go as long as their paperwork is done.

Her paperwork is done, so Beckett takes Gates at her word and is outside in less than two minutes. She'd taken the subway in today and takes it back now, but gets off two stops early, preferring to walk and savor the afternoon. She can't think of a finer time and place than early spring in New York.

Except perhaps for spring in Paris. She smiles, thinking of that surprise trip to Paris last year. She had time off for Easter weekend, and Castle had packed a bag for her, hustled her into a cab, and refused to tell her where they were going until they were at the airport. It had puzzled her at first, him wanting to go back there after all he'd been through in that city. I want to take Paris away from that time, he'd said. I want to give it new memories. And what better way than this? And if their new memories of Paris could not entirely erase the old ones, it hadn't been for lack of trying. Strolling hand in hand through the streets. Wandering captivated through the Louvre. Spending a lazy morning in bed, feeding each other croissants.

It's the smell of croissants that's brought on this wave of memory. Beckett stops for a moment, and then finds the source. A little French bakery on the corner. She doesn't remember seeing it here before; it must be new. She walks inside and soon she's got a basket full of cheeses, a couple of baguettes, croissants for breakfast, and eclairs for dessert. She gets plenty, for who knows how full the loft will be tonight or tomorrow—Martha still hasn't found a new place, and Alexis's schedule is erratic with exams looming. She's sure none of it will go to waste.

She walks a bit slower now, for the bags are heavy. She's half a block from the loft when her phone rings, and she's tempted to ignore it—probably Gates asking her to come back to the precinct—but duty calls and she stops, sets down her bags, and looks at the phone's screen.

It's Martha calling. Odd. Beckett frowns, trying to remember the last time Martha called her. Martha isn't much for phone conversations. Castle (uncharitably if accurately) says it's because in-person communication lets her indulge her flair for the dramatic in a way a phone call never could. But Martha's calling now, and now Beckett sees that there are two missed calls, also from Martha. The accordion jazz in the patisserie must have drowned out the phone's ring. She answers. "Beckett."

"Katherine, are you at the precinct?" Martha's voice is shaking. Beckett hasn't heard her like this since…since Castle's abduction. "How soon can you get home?"

"I'm almost home. What's wrong?" She scoops up the bags in one hand and starts moving toward the loft as fast as she can. "Is Castle…" She can't bring herself to finish the sentence.

"He's here. But you'd better come fast. He's…something's wrong, and I don't know what to do."

"I'll be right there," she says and hangs up. She runs as fast as she can with her heels and her heavy bags. It can't be an injury or a heart attack—Martha would have called 911.

Later she won't remember if she took the elevator or just ran up the stairs. She's almost at the door when it flies open and Martha's there. Her mother-in-law looks frightened, yes, but most of all uncertain. Something's going on that she doesn't know how to handle, and that scares Beckett even more than her phone call did. Martha may be flighty and dramatic, but there's a practical and sensible core to her nature. If there wasn't, her son would not be the man he is today.

"Where is he?" Beckett asks as she drops her purse and bags in the foyer.

"In his office."

Beckett runs to the office, Martha trailing close behind. She stops in the doorway, needing a moment to understand what she's seeing.

It may be springtime outside, but it looks like a blizzard has struck Castle's office. The floor is white, and it takes her a moment to realize that it's not snow but paper, strewn everywhere, covering nearly the entire floor. On his desk there's the now-empty wrapper of a paper ream, and as she watches a sheet of 8 1/2 by 11 slides off the desk and seesaws lazily through the air before it hits the floor. It lands next to his laptop, which is lying open on the floor. Its screen is cracked, making a distorted mess of his screen saver with its endlessly repeating admonition You should be writing.

She's about to ask Martha Where? And then she sees him.

He's in the farthest corner of the room, sitting on the floor. His knees are drawn up tight, arms wrapped around them, face buried in his arms. It's as if he's trying to be as hidden-away as possible. As she walks to him, paper crackling underneath her feet, she thinks of how small he looks. Coldness runs up and down her spine at the thought; she loves his height, his solidity. He's her shelter, and to see him like this…

She kneels down beside him. "Castle, it's me. Can you hear me?"

He doesn't respond.

The chill spreads out through from her spine to her whole body. She puts a hand on his arm and feels the muscles are wire-tight. "How long has he been like this?"

Martha shakes her head. "I don't know. I got home less than an hour ago. I assumed he was working. I wanted to ask him something so I called out to him. He didn't answer, so I poked my head in, figured he was lost in his own world." She pauses, takes a shaky breath. "He wouldn't answer, he wouldn't move. That's when I called you. What's wrong with him? Should we call…someone?"

Beckett knows what Martha means. Whatever's wrong with her husband doesn't seem to be physical. Her impulse is to call Dr. Burke, but first she needs to understand what's going on.

"Give me a moment," Beckett asks, because even though she's never seen Castle in a state anything like this, there's something familiar nagging at her. Almost like déjà vu. She sits back on her heels, one hand on Castle's arm, and it unnerves her to feel him so still and yet to feel the warmth and the beat of his pulse that tells her he's alive.

That's when she notices it—clutched in one hand is a pencil, its point broken off. And that's when she notices that the papers littering the floor aren't blank. They're covered with handwriting. Much of it is illegible scrawls and loops she can't decipher. But there's plenty she can make out, and as she tries to think of how to help her husband, words leap out at her. She sees stop and hurts and it's dark. She sees don't touch them. She sees her name.

He's back there. Wherever he was those two months, he's back there now. And she understands why this is so familiar. Because she'd been the same way a couple years back, when a sniper roamed the city and with no warning she'd find herself hiding from a bullet she knew was headed her way. She'd not even notice the bewildered looks of Castle and the boys because she was back there, locked in, trapped in the past.

That's where Castle is. The question is, how does she get him out?

She takes a deep breath, and even now she can smell the food she'd bought on her way home, its scent of buttery warmth. She remembers not the Paris trip but a time much further back. Castle at the precinct, chattering on while she tried to do paperwork, telling her about sense memory, and that the sense of smell was the most powerful when it came to building and triggering memories. She recalls scoffing at the time, not because she doubted him but because it was her role in their banter at that time.

Sense memory. "Martha, can you run get my handbag?"

If her mother-in-law is puzzled by this request, she gives no sign of it. In seconds she's back with the handbag. Beckett opens it and takes out the bottle of hand lotion—it's the one she found in her stocking on Christmas morning. Castle told her later that he spent weeks hunting for exactly the right scent, even enlisting poor Alexis in the search. It's scented like cherries with an undertone of vanilla, and she's always thought it endearing how much he loves that scent on her. Sometimes at night, as they're drifting off to sleep, he'll take one of her hands, bring it up to rest against his cheek, and breathe deep the scent of her. He did that quite often during those fraught, uncertain weeks after he was found; it soothed him then.

Maybe it will now.

She takes a dollop of the lotion and massages it into her hands and along the skin of her forearms. She lays one hand on his arm, as close as she can get to his face with it buried in his arms. Beckett resists the urge to stroke his arm, waiting to see if scent alone will get through to him.

Maybe he was right about scent and memory, or maybe he was ready to come back. Because after a couple minutes that only feel like hours, he inhales, deeply, and then sighs. A tremor runs through his body as his muscles relax; the broken pencil falls to the floor. He doesn't look up yet, and it's another endless minute before she hears his voice, a bit muffled but clear and coherent: "Kate? Tell me that's you."

"It's me. I'm here."

"The real you."

She doesn't question what this means. There will be time for that. "It's really me. It's your Kate."

He raises his head then and looks at her and his mother. He's back from wherever he's been. The next thing she knows, she's wrapped in his arms so tightly she can barely breathe. "What happened?" she manages to squeak out.

He lets her go, and doesn't answer right away. When he does, his voice is low and shaky. "I couldn't make any headway on Nikki Heat. I kept wanting to play hooky. So I tried a prompt, figured I could get something done today. I picked a random word out of the dictionary. Green. It seemed appropriate, for spring."

Castle swallows hard. "So I started writing. Just free association, starting with green and seeing where it took me. And…I don't know exactly at what point…but I was writing about what happened. Where I was. The things that…" His eyes close. "It started coming back to me. And I tried to keep typing but I couldn't keep up with it and something went wrong with the laptop, so I got the paper out and tried that way but it wouldn't stop… it…it hurt to try and stop it and…"

Beckett puts her hand on his cheek, and is relieved to hear his flow of words stop, to see him regain control. "It's all right. I'm here," she says. He opens his eyes; they're shiny with unshed tears, but as blue as ever and reassuringly sane. He takes her hand and kisses it as she says, "It's over now."

He takes her hand in both of his, eyes serious now, almost grim, as he looks at her and then at his mother, and then back to her. "It's not over. I wish it was, but I think it's just starting. Because I remember it now. All of it."