As the sentinel sped east along the cracked roadway, the signs of former human civilization faded and the Sonoran fauna increased in density in and around the berm. Brittlebrush and burroweed cracked into the lanes. Honeysuckle bloomed through the desert broom on the road’s edge. Spiny ocotillo craned in between Creosote bush. Blue palo verdes shot out sideways through spiny desert mesquites. All of this steady growth overtaking signs of mankind. A mailbox lay tilted in a clump of staghorn cholla — one of the thorned arms clasping a weathered and faded envelope. The decline of man in the desert drastically reduced the consumption of water from the natural aquifers in the bedrock — the water level now raising back to just below the surface. In the outskirts of West Tucson, small swamps suddenly reappeared where once they flourished, hundreds of years ago.
Man had looked into the stars, sent probes, and radioed messages into distant galaxies. Upon the decline, when mankind’s sanity devolved and critical thinking disintegrated into scattered thoughts, an incoming signal was detected. A solitary dull throbbing of a faraway solar mass. At first, the astronomers at Kitt Peak National Lab thought it was simply a distant starburst. But, slow and steady, the flashing signal 25,000 light-years away settled on a rhythmic oscillation. There was a code to the signal. When the lead astronomer deconstructed it, he stepped away from the laptop screen and shook his head. It was brief, perhaps cut off. It read:
The message suddenly stopped and then never reappeared. The deep listening post at Kitt Peak Lab was shut down shortly after decoding the message. The cognitive plague had found the Quinlan Mountains and a final relay was sent out from the lab to the federal government: “We are unable to provide any further utility from the research conducted here. Now shutting down and archiving all data in the wells.”
DDC39 crept through the dense Madrean foliage on the broken Tangerine Road. At nightfall, the sentinel reached Catalina State Park in Oro Valley. The clear sky alighted with the stars of the Sagittarius Constellation. Mt. Lemmon and the Catalinas in the distance, darkening the starlit sky. A Holarctic abyss. DDC39 pulled off the broken road and into a patch of saguaros — its tri-axel frame blending into the three-armed structures of the high desert fauna. A shadow rolled along the western sky. A lone turkey vulture swam in the moonlight. The purifier. It flapped its enormous wingspan and hissed into the dark. Each wave, a drumbeat into the dead epoch. A carrion predator. DDC39 shut down its core generator and followed the raptor with thermal optics. As it circled in the night, the sentinel could not determine if its pattern was around it, or something else. The sentinel began its shutdown operation:
• Solar power cell — 30%. Solar armor — 100%.
• Drivetrain — operational
• Visual/cortico/thermal/radar optics — operational
• HD/Comms — operational
• Water — 100%. Napalm — 100%
• Railgun — full capacity
• JE — found various useless things
• Shutting down core operation and initiating stand-by mode
4. Binary Idols, Dead Gods
DDC39 awoke slowly to the eastern sun at the summit of Mt. Lemmon. A light wind rustled through the Mesquite trees on the other side of the saguaro patch. The temperature began to drop slightly and the wind intensified. The branches of the mesquite swayed and entire trees bent in the gusts. The ironwood joined in and even the trunks of the saguaro swayed. A flock of tumbleweed bounded up the broken road. From the west, the sky darkened and the sun collided with approaching clouds.
DDC39 uplinked to the NOAA satellite array. Above, an entire fleet of low orbit custodians continued their tasks in the exosphere — oblivious to the human annihilation. Some, with their terrestrial systems offline, shut down and floated silently in the void. Others remained vigilant — untethered and unreliant. They recharged in the sun and adjusted their orbit. They pinged other online systems and kept this digital rhythm — an ongoing collection of data, sent somewhere in the magnetopause. DDC39 linked with NOAA 17 and its geological data. A heavy monsoon was moving northeast towards the sentinel.
With the storm, the sentinel would not be able to recharge as fast. There would be a danger of flash floods as well. DDC39 would have to get to higher ground and then wait. It unlocked and rolled back onto Tangerine Road, navigating through the fissures and fallen foliage in the street. Ahead, an Astrovan sat listless, careened into the berm. A message was spray-painted on the side: “Meghan & Dad, I love you. — Tenley.”
The sentinel continued East along the road. Soon, it opened up on each side — the foliage receding to the left and right, and a bank appearing along the middle. Tangerine Road became Highway 889 and ascended. The elevation: 2800 feet and climbing. A light trickle appeared on the roadway. DDC39 wiped the occasional drop from its optics with an autoblade. The Catalinas were close enough to make out faint animal paths along the ridgelines. DDC39 pinged again and was alerted to activity to the northeast. Thermal optics were barren — a solitary coyote bounding along in the distance. DDC39 zoomed in on the source of the activity: Oro Valley Hospital.
When the disease was understood to be in the air, there was a large migration to the desert southwest. Like the plains settlers and Doc Hollidays who flocked to the desert to seek refuge from tuberculosis, so too did the hopeful seeking to avoid PCH. The still-thinking hung onto the hope that the arid air limited the pathogen vector — even though the dwellers of Sonora reverted at an equal rate. Oro Valley Hospital — a for-profit medical center — more than doubled their beds and it wasn’t enough. A wing was constructed for the study of the disease. The other wings — oncology, neurology, cardiology — were converted to quarantine and restrained hospice. As DDC39 approached, it could see that the parking lot was full on all sides with dusty, broken cars. There were cars pulled into the desert and onto the highway berm. A single, tattered, Arizona state flag flapped in the breeze at the top of the mast near the entrance.
DDC39 steered off the highway and into the expanse ahead of the mass of cars. The sentinel switched back and forth between thermal and zoom optics, looking into the western wing of the hospital from 200 meters out. The sky now darkened to a violet and gray brume. The sun throbbing a dull white behind the clouds. Droplets of rain puffed in the calcic soil and rattled the branches of a triangleleaf bursage nearby. The lower windows were broken out but some of the 3rd floor windows were unshattered. The sentinel advanced closer and scanned the terrain around the perimeter of the hospital. No signs of visible foot traffic on the western side. It zoomed into some of the shattered windows on the 2nd floor. No visual activity. No thermal signatures. Nothing on the cortical scan. As it got closer, the rain intensified. The sun completely vanished and the monsoon unleashed on the soft, chalky desert floor. Streams of rainwater ran down the black pitchfork center frame of the sentinel. The downpour washed a thick film of dust off the railgun and optics array. The soil devolved into a soft mud and DDC39 strained in the bog as it moved closer to the western side of the hospital. At 50 meters out, the sentinel zoomed to the roof and noticed a thin white line of smoke. Almost as soon as it appeared, it was gone.
Through its lumbering toil, the sentinel made it to the stair bank on the western perimeter of the hospital — what was once the Physicians Alliance wing. It stood motionless in front of the closed beige door of the stairwell, letting the downpour wash the clumps of alluvial fan off the tri-axel and serrated tire tread. DDC39 scanned the door — it was locked from the inside. The sentinel charged up the railgun. The cannon arm swung up and gently hummed. DDC39 backed up slightly and steadied the barrel at the door lock. A single uranium round fired into the lock and obliterated the mechanism, jarring it open.