THE CRACK BENEATH THE SKIN

A blinding arc of fiery red phosphorus shot from the flare gun, shrieking through the air and embedding itself deep into the century-old, creosote-soaked timber beam directly above the central floodlights.

For a fraction of a second, nothing happened.

Then, with an ear-splitting CRACK, the structural timber detonated into splinters under the intense heat and ancient rot.

A deafening groan shuddered through the mountain. Dust cascaded down in thick, choking sheets, followed immediately by a rain of fist-sized rocks. The private security operatives opened fire, muzzle flashes strobing in the darkness, but their bullets were drowned out by the roar of the mountain tearing itself apart.

"Fall back! Fall back!" Dr. Harrison screamed, raising her arms as massive granite slabs broke away from the ceiling, crashing down upon the floodlight rigs and plunging the tunnel into chaos.

A boulder the size of a vehicle smashed directly onto the hood of the operatives' transport vehicle behind them, rupturing the fuel line in a secondary explosion of orange fire.

Ava pulled her plastic raincoat over her face, curling into a tight ball against the floor of the train car as the ceiling collapsed outward. The concussive roar pressed against her eardrums until she couldn't hear her own screams. Shards of stone ricocheted off the corrugated steel roof like artillery fire.

Then, silence.

The violent crashing subsided into a dull, hissing settling of dust. The tunnel air was unbreathable, thick with pulverized granite and sulfur smoke.

Ava coughed violently, wiping dust from her eyelashes. The entire front section of the tunnel was completely blocked by a massive, smoking wall of collapsed stone. Dr. Harrison and her security team were either crushed beneath the rockfall or sealed on the opposite side of the mountain pass.

"Ava..." a faint whisper called out from the debris beside the train car.

Ava crawled to the doorway on her elbows, ignoring the blinding agony in her broken leg.

Karen was pinned beneath a fractured wooden beam, half-buried under gravel and splintered railroad ties. Her face was gray with dust, her breathing shallow and rattling.

"Mom!" Ava tumbled out of the car, hitting the rocky ground hard, crying out as her shin twisted under her weight. She dragged herself across the gravel to Karen’s side, desperately clawing away the heavy stones covering her mother’s chest. "Hold on, Mom! Please, I'll get you out!"

"Stop... baby, stop," Karen coughed, blood bubbling at the corner of her lips. She reached up with trembling, dust-caked fingers, cupping Ava’s cheek. "There’s no time. The secondary shafts... they're venting water."

Faintly, beneath the rubble, the rushing sound of an underground river grew louder.

Karen reached into her pocket, pulling out a small, blood-stained laminated card with a telephone number and a nine-digit code scrawled in faded ink.

"Go to the service exit... behind the switcher box," Karen whispered, pressing the card into Ava’s palm. "Call this number. Ask for Julian. Tell him... the sparrow is in the storm."

"I can't leave you!" Ava sobbed, clinging to her mother's coat.