The guard waited three counts after his own voice cleared the air. Nothing came back. No movement at the base of the palisade. He took two steps off the path, pole-arm raised, and rounded the coal pile with the slow economy of a man who had learned not to rush blind corners early in his career.

The shadow was empty. A wedge of darkness laid down by the timber stack, and at the foot of it, nothing. No man or body. Not even the warm hollow that a body leaves against cold stone. He lowered his Qi feeler and reached out with the harder edge of his senses, the one that read pressure rather than presence. Still nothing.

He stood with the pole-arm half-down. A loose bit of canvas slapped on the palisade somewhere. Something with claws scrabbled briefly behind the ore carts and went quiet.

"Bah." He spat to one side and stepped back to the path. "Bloody mountain rats."

He continued the overlap, foul mood now mixed with mild embarrassment, and did not look behind him again.

A kilometre up the slope, between two flanking outcrops of grey rock that pulled the wind sideways, Lin Xuan came to rest. He had taken the first Cloud Step the instant the guard’s head turned, the second before the man’s hand finished tightening on the weapon, the third as the guard’s voice rose to call across the perimeter.

Three full bounds, low and silent over the ridge above the palisade and down through a draw that put a fold of mountain between him and the basin. By the time the call of "Who goes there?" had echoed off the eastern cliffs, he had been forty seconds gone and two ridges deep.

He pressed his palm flat against the rock and let his breath catch up with the rest of him.

[ This works. Nothing in that valley can sense what we are about to do from here. Pull the insect from your inventory. ]

’Was hoping you’d forgotten.’

[ I never forget the budget items. ]

He turned his palm up and pulled the Marrow Centipede out of inventory. It coalesced in the centre of his hand. Dark red, longer than his middle finger, segmented in plates that looked like dried blood over old bone. Two antennae flicked. Two mandibles opened and shut on nothing. It lay on his palm the way a tool lies on a bench, waiting.

"You purchased me a horror," he said, watching the antennae work.

[ I purchased you a precision instrument. We do not call it a horror. Try a command. Lift the front segment off your palm. Use the kind of thought you use to send Qi to your sword. ]

He concentrated. The front three segments of the centipede lifted off his skin in a slow, jointed motion. The mandibles opened wider. He lowered the thought, and the segments lowered with it.

"Oh," he said quietly. "That’s worse."

[ That is excellent. We are going to do better than excellent. ]

A second panel bloomed at the corner of his vision, smaller and dimmer than the standard one. It showed an image: the inside of his own palm, viewed from two finger-widths above. Curve of his thumb. Lines of his life. The dark edge of the centipede’s own head poking into the frame.

[ Visual feed. From its eyes. You will see what it sees in parallel with what your own eyes give you. Try not to look at it for very long when you are also walking, or you will hit a tree. ]

’This is the most useful and the most disgusting thing you have ever given me.’

[ You are welcome. Set it on the rock. We are going to walk it into the mountain. ]

He set the centipede on the granite at his feet. It did not move until he thought forward, and then it moved fluidly, easily, the way a snake moves across a wet floor. He watched it slip down off the rock and threaded a clear instruction into the back of his mind. Down to the basin. The crack at the foot of the palisade. Stay in shadow. It went.

In the panel, the world shrank to a tunnel of grass-blades and pebbles and the long forward perspective of something with too many legs. The centipede covered ground astonishingly fast. Inside two minutes the timber stack appeared in the feed at the edge of a broken ant-hill. Inside three, the centipede was inside the foundation crack at the bottom of the palisade and into the mountain.

’Mira. Are you sure he won’t sense it?’

[ Difficult. The mine has insects. A great many of them, by the dampness of the lower galleries. Ours will smell like one more of them to a passive Qi field. And the man may be asleep. The conversation we overheard suggested he is on the night-end of his rotation, which means he is in his quarters. If he is asleep, even his passive defence will be low. ]

’I hope you’re right.’

[ Walk the bug, Xuan. Worry less. ]

He walked the bug. It moved through the lower workings the way water moves through a drainpipe: by smallest available path, by least visible route. It slipped under rotting timber, climbed a wall of damp stone, dropped two levels through a vertical drainage shaft Mira flagged with a soft blue line. As it travelled, her overlay drew. Galleries appeared in the map that had been blank twenty minutes ago. The third level filled in chamber by chamber, passage by passage, around the centipede’s path.

[ I am mapping as we go. I will hold the third level for you to copy onto paper later. Keep moving. ]

The centipede crossed a chamber of stacked crates, navigated around a sleeping cat that did not stir, and slipped under a heavy door at the end of a corridor whose pit-props had been cut from much older wood than the levels above. It came out the other side into a small room with one cot, one lamp, one wash-basin, and one man.

Lin Xuan’s breath caught.

Elder Han Ying lay on the cot on his back, one forearm thrown over his eyes, his other hand open on his chest. He was older than Xuan had expected, with a grey-streaked beard and the long line of an old scar across the jaw. But the Qi that moved through him at rest was a deep, dark river that even at half-tide outweighed anything Xuan had ever shared a room with. His breast rose and fell in the slow rhythm of true sleep.

’There he is.’

[ Good. We are lucky. He is sleeping deep. Walk it up the cot. Right cheek, then nostril. ]

’Through his nose? Seriously? Won’t he feel that?’

[ It is the safest port of entry while he is unconscious. The insect is small enough to ride the breath in. ]

’And if he wakes up?’

[ If he wakes, he can pour his entire reserve into purification and he will not get it out. The bond is to you, not to a foreign object. His Qi will read it as part of his own system within thirty seconds. He will think he ate something bad and go back to bed. ]

He breathed out very slowly. ’Alright. That’s good. That’s going to be very, very good when we move on the mine.’

[ It is going to be everything. Walk the bug, Xuan. Gently. ]

He walked the bug. In the visual feed, the centipede climbed the leg of the cot, threaded between two folds of grey wool blanket, and emerged onto the elder’s chest. The cot timber creaked once under its own ageing. Han Ying’s breast continued to rise and fall in its slow river-rhythm.

The centipede crossed the chest, crossed the shoulder, climbed the side of the jaw and onto the cheek, careful not to disturb the scar tissue. It paused at the rim of the right nostril.

Lin Xuan, a kilometre away with his back against grey rock and his palm flat against stone, did not move.

He sent the last command.

The centipede lowered its head and went in.