A/N: This is an alternate ending from Disciple. I think it was too easy for Castle to simply tackle the suspect, and I just wanted more. So, so much more.

"Be careful," Castle said to Kate. He wanted so much to grab her and plant a kiss on her lips before she turned back to Ryan and Esposito, though if he was really honest with himself, he wanted to ask that she not go up there. If he had to stay behind, then he wanted her to stay behind with him and remain safe for him. However, he knew how important this was. He had made the connection to 3XK, even if Kate didn't want to believe it herself. He would prove himself right, not for the stroke to his ego, but for the blow to 3XK's. He wanted that son of a bitch in irons, pulled apart by horses, and he wanted to do it himself.

Kate just didn't understand. Perhaps she had hit the nail on the head. He wore his guilt on his sleeve, but she was just so adamant that Tyson was dead. Part of him wanted to blame her for not trusting him, but he supposed he could understand. After all, she did have a pretty valid argument. Shot several times, hundred foot drop. Those were both pretty damning, but in his very core, he believed Tyson was alive.

Every passing second translated to the thundering beat of his heart in his ears when Kate, Ryan and Esposito moved at a cautious pace up to the motel room Jerry Tyson had once stayed in and outsmarted him. Castle clenched his teeth as the memory came flooding back to him, clear as day and as vivid as his own nightmares that somehow, when Kate slept in his bed, he did not have. She was his rock, and she didn't even know it. There had been nights since they had gotten engaged when she hadn't shared his bed and those nightmares had returned with a vengeance.

As he stood there, fists clenched at his sides, every second was too long for him. The team burst into the room and he held his breath, waited for gunshots, anything that would tell him what was going on in there. It took every ounce of effort not to follow them up those stairs, where the memory of what happened that fateful night years ago would freshly assault him. Perhaps Kate had been right to ask him to stay there, even if she had a different reason for asking him to. God, he wanted to rush up those stairs, be hot on Kate's heels because damnit, they were in this together. How could she do this to him? Not arguing with her seemed like a good idea at the time, weighed down by how serious the situation had become, but now… now… now he couldn't stand the waiting and the not knowing.

In the midst of his own internal freak out over Kate's well being, he looked around, vigilant. That's when he saw him. Matthews, sneaking away behind cars, strolling as though he had nothing to worry about, the same way Tyson had managed to escape just mere seconds before the cavalry came to save his life.

Castle moved, mindful of the patch of glass just off to the side where one car had rearended another. He felt like something of a tiger, ready to pounce on his prey. It was primal. It was instinctive. He hid behind a car as Matthews headed for the gate. Seizing his opportunity, he ran. The movement startled Matthews, and Castle tackled him to the ground. A few cracked ribs later, Castle pulled the murderer up by the lapels of his shirt. "Where is he?! Where's 3XK?" Castle demanded answers, felt himself wanting to cross certain lines that would be unforgivable to get there. He had done it once before, and though none of his family was in danger at this very moment, they were all in danger, nonetheless. Jerry Tyson was meticulous, and by framing Castle for murder last year, he had proven to be more of a problem than any of them could ever imagine.

Even though Matthews was in pain, Castle's brow furrowed at the smile on his face. He missed the flash of steel in the street light, gasped sharply as it sliced through the unprotected side of the velcro straps of his bulletproof vest. His grip on Matthews' collar tightened with the pain, fists curling desperately as he struggled to breathe. His eyes widened as the knife was pulled out of him, as though he was nothing more than a soft stick of butter. Blood seeped out from the slit in the navy blue armor. The second strike was more jarring, and a small, barely there cry escaped Castle's lips.

Matthews pushed at the writer, and it didn't take much for him to topple over onto his side and pull the knife out, struggling for air, writhing in pain. Matthews struggled to his feet, and looked down at Castle, his hand wrapped protectively at his right side, applying the needed pressure to the two stab wounds residing there. "Oh, you don't know how easy it would be to kill you right now," he said, wincing. "Let your detective lady friend find you lying in a pool of your own blood. This is what you get for sticking your nose where it doesn't belong." Matthews looked at the blood dripping from the hunting knife and opened the gate. He looked back at Castle, shaking his head. "After everything I've heard about you, Mister Castle, I am underwhelmed."

Castle cast him a loathsome look. Adrenaline was all he had now, and surged forward, reaching out to grab an ankle, a pant leg, hell he'd settle for a shoelace if it meant it would trip Matthews up down the line. He missed. "NO!" he cried out as Matthews turned around and disappeared, leaving Castle to press his shaking hands back to his side.

A/N2: Continue? Abandon? Reviews give me muse.