Isabelle had experimented with inhabiting all sorts of materials, from steel to sand and stone to quicksilver, anything that had never been alive, and every substance had its own feel. In hammered steel she could feel the edges where slivers of sharp iron fitted together. Glass felt like swimming through taffy, and quicksilver was dark and heavy in her breast.

But quondam artifacts were different. The Builder and his workshops had filled their devices with gears and axles, catches and punched ribbons that turned along axes the mind could not see and filled up spaces that should have interfered with one another.

Most of the artifacts Isabelle had got her hands on were mere fragments of broken devices, machines of adamant torn apart in the Breaking of the World. Inhabiting them was like swimming through a collapsed clock tower filled with shattered bits of nonworking machines, the purpose of which she could only speculate upon.

The key was different. All of the ratchets and springs remained intact. She flowed through their structure like the shadow of a hawk across the top of a cloud. She looped through the wheels like a rope through a series of pulleys, block and tackle designed to move not pallets of freight but spools of information. Yet though the ring hummed and thrummed with life, it slept deeply, unperturbed by her presence, and none of the gears would shift at her urging. Around and around she wound until at last she reached a gap, a space where a cog of many planes was missing. Here there were release mechanisms and flaccid springs, higher-dimensional axles that had no other end. This was the shape of the lock and the key, two halves of a whole greater than the sum of both.

She could have spent hours puzzling out the intricacy of the space, but she’d discovered what she came for. She withdrew the way she came, spooling herself back into her body until finally the last thread of her sorcery detached from the ring like pulling a burr out of a wool coat. The sensation of inhabiting her own flesh made her skin shiver. Her ancestral chorus hissed and roiled like a nest of snakes, reminding her just how blessed the silence inside the key had been. Alas that she could not trust them to remain quiescent when she was away. Ever she feared to return to her mind after an excursion to discover that it had been occupied in her absence.

She had indeed slumped over but someone, Bitterlich probably, had laid her on a cot. She rubbed her face, finding her burn scar rough under her fingers. After a moment, she stood.

“Did you learn anything interesting?” Bitterlich gave her a politely questioning look, whiskers twitching, which had the irritating knock-on effect of making her want to grin. She resisted. Mostly.