Gunfights.
Car chases.
Explosions.
He even once got kidnapped (twice, if you counted the time in Paris).

But nothing —nothing— prepared him for the fear that slammed into him the second he saw Kate Beckett tied to a chair, blood trickling down her temple, and a gun pointed at her head.

His blood turned to ice.

Beckett.

His partner.
His love.
His reason.

The kidnapper — a wiry man with dead eyes — barked orders at the ESU team surrounding the abandoned warehouse.

"Lower your weapons! I swear, I'll blow her brains out!"

Castle, crouched behind a patrol car with Ryan and Esposito, didn't think.
He couldn't.

Instinct — pure, primal — took over.

Hemoved.

Darted from cover.
Heart in his throat.

"Castle, NO!" Ryan shouted behind him.

He ignored them.

Because Beckett wasn't just a cop.
She wasn't just the strongest woman he knew.
She washis everything.

And she needed him.

Castle burst into the warehouse, hands up.

"Wait! Wait!" he called. "You don't have to do this."

The gunman whirled toward him, panicked.

Beckett struggled against her bonds, screaming through her gag.

Everything slowed.

Castle saw the man's finger tighten on the trigger.

And without thinking — without hesitation — Castle lunged forward.

Bang.

The gunshot cracked like a whip.

Castle stumbled mid-step.

Something hot and sharp ripped through his lower back.

He collapsed hard onto the cement floor, pain screaming through his body.

The world tilted, blurred.

Above him, Beckett's muffled scream shattered the air.

Shots rang out — not at him this time — as Ryan, Esposito, and the ESU team stormed in, taking down the gunman in a flurry of movement.

Someone was shouting his name.

Castle tried to speak, tried to move —
—but he couldn't.

He couldn't feel anything below his waist.

The Last Thing He Saw

Beckett tore herself free.

Her hands, slick with blood, scrabbled at his chest.

"Castle, stay with me," she begged, voice cracking. "Stay with me, Rick. Please."

He tried to smile.

Tried to tell her it was okay.

But darkness was already pulling him under.

And the last thing he saw before everything went black was her face —
Beautiful.
Broken.
And full of love.