Heavy footfalls echoed in the loft. Castle raised his head at the sound, trying to figure out where it was coming from. He struggled against his restraints, seeking his mysterious captor.

The man came up from behind him, startling Castle. He sneered at the weakness he saw. So pathetic. The writer restrained before him would be too easy to break. The man could already tell the earlier attack had had its desired effect. Dried blood coated the side of his captive's face, originating from a nasty wound above his right eyebrow. He was also hunched in on himself, with bowed shoulders, trying to lessen the pressure on his bruised stomach. Oh, this is just the beginning, the man thought sadistically.

"Now. Mr. Castle. Hello, you with me? Good, good. My name is of little importance. But, you may call me… Derek. Yes. Derek is the perfect name." The man laughed at his clever choice for a name. Named like the hero in your precious books, Mr. Castle. Oh, the irony, oh the cleverness! "Now with that all settled, let's continue, shall we? I am here for revenge, as I stated previously. And do you know what I want revenge for?"

The man's question took Castle by surprise. His blank expression must have been answer enough, as the man continued.

"No of course you don't. Well, I have decided to divulge to you the reason I targeted you. Are you ready to hear this?"

Castle just stared at Derek, uncertain what he was going to say. A disgruntled fan? No don't be silly Richard. Someone from his past? Maybe.

Before Castle could come up with another scenario, the man crossed the distance between them, setting his hands on the chair arms, a stony look in his eyes.

"You murdered my brother, Mr. Castle. It may not have been you who personally killed him, but you and Detective Beckett arrested him for a crime he didn't commit. He died in prison last week. I have you, and you alone, to blame for his death. And I will make sure you feel the pain I felt."

Your brother? Castle was having a hard time keeping up with what his captor was saying.

"I-I don't know what you-you are talking about," Castle sputtered out, trying hard to focus on the violent words being thrown his way.

The man's expression suddenly morphed, as if a switch had been flicked. With a large swing, he lashed out a fist and it connected with Castle's chest with a sickening crack. Castle's breath caught in his throat as the air was stolen from his lungs. Pain flared up from his ribs and he clenched his fists tightly, trying to ride out the wave of agony. I'm just a writer; it's supposed to be a non-violent profession. Where was this in the job description?!

He was finally able to draw in a breath after what seemed like hours. It had really only been a few, pain-filled seconds. Castle shut his eyes and kept his breathing shallow, not wanting to aggravate his throbbing chest. He only opened his eyes when he suddenly felt the man's warm breath in his face.

The anger in the man's eyes diminished to a mere glimmering ember, either to die out, or be brought back to life.

"Rule number two, Mr. Castle. Or have we already forgotten? I am a no-nonsense kind of man and I will not tolerate your lies!" Derek whispered menacingly in Castle's face. Castle would have almost preferred to have been yelled at. The whole whispering thing sent chills down his spine. It made his gut twist uncomfortably and the effect was even more terrifying.

Castle attempted to shrink away from the crazed man with a wild glint in his eye, but it only resulted in intensifying his pain as the movement strained his burning chest. Fresh pain snaked its way into his awareness and he hissed in discomfort. Ribs. Possibly broken, definitely hurting. The man watched with pleasure as pain flitter across his captive's face and continued his whispered threats.

"You do know of whom I am speaking. You and that detective friend of yours put my brother in jail for a crime he didn't commit! He was innocent and you put him in prison with drug lords, thieves and murderers! Two months into his sentence, he was shanked in the yard. Died, bleeding out, and all alone. I want to be sure you suffer the same fate."

Castle's eyes hardened at Derek's words. So this psychotic SOB's out to get me because Beckett and I put his brother away in jail? We put so many people away it's hard to keep track of them all. Something about the shanking in the prison yard sounds familiar, like I'd heard it somewhere recently…

Castle briefly closed his eyes, trying to get his thoughts sorted out. I need to remember all that I can about this guy. If I can learn more about him, maybe I could use that information to my advantage… Focus Rick! Focus! Okay, all right, remember what he's been saying. He said his brother went to jail for a crime he didn't commit. Typical. He was shanked and bled out. He's obviously seeking some sort of justice for his brother's murder. He blames Kate and I…

Castle's eyes snapped open at that thought. Ignoring the throbbing in his temples, and the ache in his chest, he locked eyes with Derek and asked, "You want me to suffer the same fate? Just me?"

"Just you? Why no, Mr. Castle. Detective Beckett will most certainly suffer as well."

Castle's stomach flipped at Derek's words.

"But her suffering will be…psychological, if you will, not physical like yours. You see as much physical pain as I can cause her, it would be even more fun to torture her mentally! I'll be sure she's the one to find your body. The pain and guilt she'll feel after seeing you murdered, will be better than any torture I can inflict on her. Killing you, her partner, will the best revenge."

Castle swallowed at the man's revelation. He couldn't let this man win. He couldn't let Beckett find him broken and beaten. He didn't want Beckett to think that he'd given up…stopped fighting...

He shut his eyes as he realized how deeply it would cut her if she found him bled out and murdered. She'd be sure to flash back to her mother's murder. He couldn't be the cause of all that pain. He couldn't bear it.

He wouldn't lose; he wouldn't give in. He'd stay strong for Beckett. With a newfound resolve, Castle opened his eyes and gave Derek the coldest stare he could muster.

"Bring it on."

Derek looked down at Richard Castle, the critically acclaimed author of crime novels, and frowned. At the beginning, the author had seemed so compliant, so pathetic. But now, the author was fixing him with an icy, defiant stare. Where had the submissive author gone?

The man reviewed his recent taunts, pacing the floor in thought, flicking his gaze over to his captive appraisingly as he went. Castle just kept glaring at him, a fierce look in his sea blue eyes. The man suddenly stopped short, and turned slowly to face Castle. An evil grin spread across his face as the light bulb clicked. She was the key. She was his weakness. Oh, this…this can be useful.

Looking at his prisoner now, he could tell something had changed. A rebellious air had enveloped Castle. He made bold eye contact, and didn't slouch his shoulders. Creases at the corners of his eyes and a clenched jaw told Derek he was still in a decent amount of pain. But it never blatantly showed; he was hiding it well. A fresh confidence had found it's way into his captive. That will only make you more fun to break, Derek thought wickedly. And I know exactly how to do it.

"But then again, physically torturing her could be just as fun…"

Castle's eyes widened, and anger turned his vision red as he struggled savagely against his restraints.

"I swear if you lay one hand on her Derek! You can do anything to me…just leave Kate out of this. Leave her alone!" Castle bellowed at the man, ignoring the biting of the zip ties, ignoring any and all pain, as he tried to leap from his chair. There is no way he's getting to Beckett. No way.

Derek threw back his head and laughed maniacally. He wanted to give himself a pat on the back for his fantastic intuition. So she really was Castle's weakness, his pressure point. It had been so easy to get a rise out of him.

"Leave her alone?" Derek asked suggestively, drawing out each syllable. "Why should I?"

"You have me, Derek," Castle reasoned. "You can do anything, anything to me! You don't need her. You said so yourself, it will be torture enough when she finds my…body. Just don't hurt her."

Castle cringed at the pleading sound of his voice. But he had no choice. He couldn't let anything happen to Kate. Just the thought of this man harming her made his stomach revolt.

"Anything?"

Long fingers extracted a combat knife from a jean pocket. Derek slowly and meticulously opened the blade. He ran a finger along the smooth surface that glinted in the dim light. Castle's eyes opened wide at the object in his captor's hand, but he refused to say anything. He watched as Derek casually walked ever closer, the knife griped in his left hand.

Castle took a calming breath and met Derek's predatory gaze. With as much courage as he could muster, Castle responded.

"Anything."