((This is an alternate ending for 5x05.))

Gunshots rang through the air as Beckett walked towards the black SUV, her finger steadily pulling the trigger with each step it took her to close the distance between her cruiser and Tyson. As she moved, she kept thinking to herself, 'Finally, you son of a bitch.' His body was slack in the driver's seat, and she was sure she had hit him, that it was finally over and justice had been served. Relieved, she began to lower her gun, and as she was about to take a deep breath, a momentary sigh of 'Thank God', the car door swung open, knocking her backwards as though she were stuck inside some pinball machine. As she landed on the wet cement of the bridge, she grunted and the last of her air was expelled from her lungs.

Castle watched from the passenger seat of the unmarked police car as Beckett went down and Tyson got out of his SUV with his gun drawn. He thought it was going to end right there. All it would take was a single bullet and his life would come crashing down around him. His heart thumped in his chest and his head throbbed. He frantically looked around the interior cruiser and hoped there was something there that could help him – help Beckett – get out of this alive. "Castle! I got your girl!" he heard.

He opened the glove box, not at all surprised to find there was no gun stashed away in there. He could hear Kate moaning, and he moved faster, only to be held back by the seatbelt. "Ugh," he growled to himself and wrestled with the buckle, finding it wouldn't come undone. His hands shook as fear took hold of him.

"Are you watching? I want you to see this!"

He angled his head to try and get a better view of where Tyson was standing, his throat seizing as he saw Kate, completely at the serial killer's mercy. "You think that I'd let you live, after everything you've done?" He muttered as he shuffled his hostage towards the passenger side of the wrecked car.

As Castle searched, he realized that this was real, and it was happening. His worst dreams were coming true.

Keeping his head low, he managed to get his seatbelt off and moved his hands under the seats, blindly searching for something – anything.

"Castle, come on! I want you to watch!"

His voice is getting closer, and Castle crawled out the driver's side door. The second he was out, he thanked his lucky stars for Tyson's carelessness as his eyes landed on Beckett's discarded piece. "I want you to watch as I take her life!"

He could feel the desperation welling within him, the willingness to do whatever it took to get Kate out of Tyson's arms and back into the safety of his own. Many nights he had woken up to such nightmares where he failed, and he refused to believe that this was going to end the same way. His hand wrapped around the hilt of Beckett's gun. It was heavy, yet comfortable in his grasp. Everything was silent for a moment, and Castle chances a glance through the rear window and he knews Tyson had seen he was gone.

Castle gets to his feet and lifts the gun over the roof of the car. "Over here," he called. Tyson and Beckett turn to face him, and Castle took careful aim and fired. Beckett dropped to the ground with a grunt, and for a split second, Castle thought he hit her. He had a certain level of confidence in his shooting skills, and he was positive that she was fine.

More gunshots rang through the air as Tyson stumbled backwards. The writer continued to fire the rest of the clip at the man who was responsible for so much pain. He felt a sinking feeling settle in the pit of his stomach when Tyson tumbled over the edge of the bridge.

Beckett stood up, her eyes fixated on the spot where her captor disappeared, and with caution, she approached the edge to look down upon the frigid waters below. She breathed a sigh of relief, certain that he couldn't have survived. Castle had hit him. Castle?

She turned back to the cruiser. He was still standing there, gun drawn over the roof of the car. She could see the slightly jerky movements of the weapon that Castle was shaking, and he had every right to be. Taking a life wasn't supposed to be easy, and it wasn't supposed to be something someone could get over.

The detective moved around the car and came up beside her partner. Sweat glistened on his face, his breaths were ragged. Her gun continued to shake in his hands and she reached for it. "Castle," she said softly, encouraging him to let it go. His grip was tight. "Hey," she breathed. "Rick. It's okay. Let it go."

She managed to pry her service weapon from his grip and placed it back in her holster. She looked at him, concern growing on her face. She gently touched his arm and gave it an affectionate squeeze. "Rick?" Still, he hadn't turned his head to face her. All she was rewarded with was a breathy groan from the back of his throat as he struggled to take a breath. "Hey!" she said, and physically urged him to face her. If she could just capture his eyes, she might have a better chance of reaching him.

When she was finally face to face with him, her smile was short lived as he began to fall. "Castle!" she cried out, her arms wrapping around him in an attempt to keep him upright. He was too heavy for her, and the best she could do was keep him from hitting his head on the pavement. "Castle? Castle!" his surname escaped her lips by second nature. Something was very wrong.

In the dark, and with his dark clothes, it was difficult to spot until her hand came away wet and red. "No," she breathed, tearing open his shirt. "No." Kate said again, feeling defeat rising in her chest at the sight of the blood seeping out from him. "God, RICK!" She pressed her hand over the gunshot wound just under the right side of his ribcage and looked at his face, his head deliriously rolling from side to side.

"K… Ka… Ka'e…" he tried to speak her name. For a moment, their eyes connected, then his closed and she suddenly felt alone.

"Castle!" Beckett's fingers deftly felt for a pulse. Her heart felt like it stopped beating, too, when she couldn't find a pulse. She cursed loudly and repositioned herself next to him. Headlights came down the road when she began compressions. "I will kill you if you die on me," she promised – but she would have plenty of time to think about what she just said, later.

"CASTLE!"