Chapter 20: Zero-Nine's Body Has an Opinion

The obsidian circuit line nearest to Zero-Nine's left boot was emitting a frequency she could feel in her back teeth.

Not metaphorically. Her molar implants—the pair of ceramic-coated sensor nodes grafted into her lower jaw at age nineteen, the ones that had saved her life twice by detecting subvocalized threat commands before they reached the speaker's lips—were vibrating at a pitch that sat precisely between useful and unbearable. She had been ignoring it for four minutes. She was becoming less successful at this.

She moved eleven meters south along the circuit perimeter, away from the carved channel where Cass was crouching and explaining geometry to Elian in rapid, precise sentences. The vibration in her jaw followed. The circuit lines in this terrain ran beneath every meter of the obsidian platform, and she was standing on top of all of them, and there was nowhere on this ground that was not conducting.