He changes the ending of Heat Rises as soon as he returns from the hospital, because a happy ending doesn't seem right anymore, because life is fragile and Castle keeps waiting for a round of bullets to smash through the windows of his apartment.

It never happens.

But that doesn't stop him from imagining. On days when he is especially haunted by memories of Beckett's eyes slipping closed and her blood pooling underneath his fingers, Castle sits and stares at the windows, waiting. If he's in a poetic mood he focuses on the splintering of the windows as the sniper's bullets burst through the glass, and the sharp contrast that would be made by the glinting slivers of glass amid the pools of his blood. Often times though, Castle's not in that kind of mood and he focuses on the violence of the scene instead, the hot rawness of it all.

He decides that it's not healthy.

He continues to do it anyway.

"Dad?"

Castle's gaze stays fixed on the windows. "Hmm?"

"What are you doing?" Alexis sounds worried, concerned. Castle keeps his attention on the overcast sky and can almost hear the crack of a gun and the tinkling of glass hitting the floor. "Writing a death scene," he admits finally, his voice too detached and vacant as he tries to picture exactly how his blood would seep into the carpet.

"Whose?" Her voice sounds suspicious now, and Castle begins to wonder if maybe she understands.

"No one's..." he trails off and skims his hand along the back of the couch. "Just a death scene," he adds.

He doesn't have the heart to tell her that it's his.

XXX

She cries when she reaches the last page of Heat Rises.

Rook being shot could not have been Castle's first choice for an ending. But when Beckett reads it again (and again and again), she realizes that the ending became a foregone conclusion as soon as she was lying in the grass with her blood all over Castle's hands.

When Jim walks into the room he pretends that he can't see her tears. "Good book?" he asks, pointing to the pages open in front of Beckett while pretending not to notice the author's name printed at the top.

"He wanted to save me," Beckett says softly. Jim stares at her steadily and waits. "He shot Rook," she half whispers, and runs her fingers over the last few words on the page.

"He shot Rook," Jim echoes back to her, and Beckett can tell that he doesn't totally understand.

She is Nikki, and Rook is Castle, and putting Rook in the hospital with a serious gunshot wound is probably akin to Castle cutting off his own arm. But she can't find the words to explain that.

"He loves you," Jim says suddenly, and Beckett flinches. "I heard him say it to you, in the cemetery, while he was desperately trying to keep you alive."

Beckett shuts Heat Rises and taps her fingers against the silhouette on the cover. This isn't a conversation she wants to have right now.

"You heard him." It's not a question when Jim finally says it, and Beckett just sighs. "You could do a lot worse, you know, than a man who wants to take a bullet for you so much that he shoots one of his fictional characters," he adds when he realizes that she's not going to say anything.

Beckett half laughs. "That's a first for me, I suppose."

Jim grins, but then becomes serious once more. "You're going back."

"Is that an order or an observation?"

"A little of both, I think."

Beckett bites her lip and then stands up from her chair, balancing Heat Rises in her hands. "I know I can't hide forever."

Jim looks up and gives her a small smile. "Well, you have to go back and try to give that book a better ending anyway," he says, and Beckett realizes that maybe he's understood all along.