Caleb's Hand . . I watched my brother's hand disappear behind his back, and eleven months of combat training took over before conscious thought ever caught up.

"Get down!" I barked, grabbing Elena by her tactical vest and pulling her over the desk just as the heavy glass windows of the study exploded inward in a shower of razor-sharp shards.

The deafening roar of a modified Black Hawk helicopter filled the room, its blinding searchlight sweeping across the shredded drapes and wooden furniture. High-caliber rounds chewed through the walnut paneling, turning antique books into clouds of white confetti.

"CID! COVER!" Elena shouted into her radio as her two remaining field agents in the hallway returned fire toward the snow-covered lawn outside.

I stayed low, crawling across the carpet toward the fallen desk drawer where I knew my father had kept his old service weapon. My fingers found the cool steel of the .38 revolver. I pulled it out, checked the cylinder—six rounds of .38 Special—and tucked it into my belt.

"They're not local law enforcement!" I shouted over the thunder of the helicopter engine. "Those are private security operatives! They're here to sanitize the scene and execute anyone inside!"

"My agents are pinning down the front entrance!" Elena yelled back, pulling her Sig Sauer 9mm pistol from her holster. "We need to get the hard drive out of here! The physical drive is still plugged into my terminal!"

I ducked beneath a second volley of gunfire, lunging toward the coffee table. I ripped the USB drive from the laptop port, shoved it into my pocket, and grabbed Elena by the arm.

"The service tunnel!" I said. "My grandfather built an underground storm escape route under the wine cellar during the Cold War! It leads to the old boathouse half a mile down the ridge!"

We scrambled out of the study into the main hallway, where smoke and the acrid smell of burnt gunpowder hung thick in the air. The two CID agents were providing suppressive fire toward the front porch, where four figures dressed in unmarked black winter gear were advancing through the shattered front door.

"Fall back to the basement!" Elena commanded her men. "Move! Move!"

We retreated through the grand kitchen, kicking open the heavy oak door that led down into the stone-walled basement. I slammed the door shut behind us and threw the heavy iron bolt into place.

Seconds later, heavy boots thundered against the kitchen floor above us, followed by the muffled impact of tactical breaching charges being slapped against the door frame.

"We have thirty seconds before that door blows," I said, leading Elena and her agents through the labyrinth of dusty wine racks toward a heavy iron grate set into the far stone wall.

I grabbed a steel pry bar resting on a nearby workbench, jammed it into the rusted padlock securing the grate, and put my entire body weight into the lever. The old lock snapped with a sharp crack.

I pulled the heavy iron door open, revealing a dark, damp stone tunnel stretching into the pitch black below.

"Go! All of you!" I ordered.

"Daniel, you're coming with us!" Elena insisted, lingering at the threshold.

"I'm right behind you," I said, pulling the .38 revolver from my belt. "I'm going to drop the support timbers on this side of the tunnel once you're through. It'll block their pursuit and buy us time to reach the hospital."