The whimsical code phrase, matched to a recording of his own voice, triggered the door to open. In a clearing just beyond the split tree, a large grassy section of ground slid back to reveal a steep broad ramp leading downward into the earth. Birk and Arthur strode down the slope, and the cover slid back into place over their heads as soon as they’d passed. The two continued down the ramp until they were ten meters below ground and their progress was stopped by a heavy metal wall in front of them.
If they’d been unwelcome intruders, the city’s defenses could have disposed of them in a number of ways at this point; the methods ranged from poison gas to energy explosions. Birk merely repeated his name aloud, though, and the heavy wall slid aside to allow the man and the robot to pass. In al
