"Recalculating," the voice said. It wasn't the standard digital female voice. It sounded like a woman whispering through a heavy rainstorm.

Software Update Required, the screen read. To continue to your destination, please provide: Heartbeat.

As he pulled out of his driveway in suburban Taipei, the GPS screen flickered to life. The startup splash screen wasn't the standard Garmin logo; it was a grainy, high-contrast photo of a mountain pass he didn't recognize.

He looked at the RAR file’s properties on his phone, which he’d synced to the car's Wi-Fi. The upload date wasn't 2014. It was tomorrow. "Arrived," the GPS whispered.

"In two hundred meters," the voice whispered, "turn into the mirror."

“The roads change when no one is looking. Do not follow the blue line after midnight.”

Chen looked up. The office building was gone. In its place stood a mountain pass, and the air smelled of wet earth and ancient electricity. He looked down at the Nuvi. The firmware version had changed. FW 5.00: Ascension.

It was supposed to be a simple firmware update for an obsolete Garmin unit—a favor for his grandfather, who refused to use a smartphone. But the "1722" suffix was wrong. Taiwan’s map codes didn’t run that high back in the 2010s.