Mara Quill knelt in six inches of gray water and counted the broken glyphs on the tunnel wall. Last night she had set forty. This morning twenty-two were smashed, and a fresh crack ran through the stone where her charm-anchor used to hold. Someone had come down here after her shift. Someone knew what she was doing, and she had told no one. She had been working this tunnel for eleven months. Above her, in the old plaza no one crossed anymore, a heart-shaped billboard hung dark on its iron mount. Forty years ago it had lit the whole quarter, and every witch in the city had gathered under it that last night to watch it die. No one talked about why it went out. Mara had decided, alone, to bring it back. The wiring for the billboard ran down through this sewer, through the wall she was rebuilding, into a charm-focus she had spent her savings to buy. If the wall did not hold, the focus would not hold. If the focus did not hold, the heart stayed dark. She waded to the crate where she kept her tools and pulled out the wrench. The wooden sign she had nailed at the tunnel mouth still read Under Construction in her own paint. Below it, in smaller letters, she had written Municipal Repair, Do Not Enter. That was the lie that kept the inspectors away. It should have kept everyone else away too. Mara did not go for the guards. She did not go home. She sat on the crate with the wrench across her knees and waited. Six hours passed. Water dripped. Around midnight a boot scraped stone at the far end of the tunnel, and a lantern swung into view. The figure stopped when it saw her. It was an older woman in a charm-worker's coat, hood up, hands empty. She did not run. She said Mara's name like she had known it for years. "You shouldn't be doing this," the woman said. "You don't know what that light was for." She set the lantern down and stepped into the water. "Go home. Tomorrow the wall will be gone. The day after, the focus. I will keep coming until you stop." Then she turned and walked back into the dark, and Mara heard the far grate clang shut behind her. Mara stood in the water a long time. The sabotage was not random. Someone in the city remembered the heart, and wanted it to stay dark. She waded back to the broken wall, picked up the first cracked stone, and began setting it again.

Three nights after the older woman's threat, Mara reset the last of the broken glyphs and climbed out of the tunnel with mud to her knees. She kept her tools in a canvas bag now and left the wrench at home. She could not risk another confrontation before the wall cured. She took the long way back through the market, past shuttered stalls and a lamplighter mending his pole. Halfway across the fish square she heard a second set of boots keeping her pace. When she stopped, they stopped. When she turned, a small figure in a tall hat slipped behind a barrel. Mara knew the coat. It was cut the same as the older woman's, but shorter, and the hat above it was pointed and worn soft at the brim. A second charm-worker. Younger. Sent to follow. If Mara walked home, this one would learn where she slept. If Mara walked to the tunnel tomorrow, this one would learn the mouth of it, and the painted board she had nailed there that read Under Construction. Then the billboard was finished. She changed her route. She turned down a lane of herb shops and stopped at the one still lit. Bundles of lavender and rosemary hung from a string above the door. Inside, a shelf of small labeled bottles ran the length of the wall. Mara asked the woman at the counter for valerian and a length of the dried garland. She paid slowly. Through the window she watched the follower stop across the lane and pretend to read a notice. Mara bought a second bundle of herbs and asked the shopkeeper for the back door. The shopkeeper looked at her, looked at the window, and pointed with her chin. Mara went through a storeroom that smelled of dust and mint, out into an alley, and around three corners before she stopped. She waited a full hour under a broken gutter. The boots did not come. When she finally moved, she did not go home and she did not go to the tunnel. She went to a boarding house two districts over and paid for a bed under a false name. She sat on the mattress with the herbs in her lap and understood two things. The older woman was not working alone. And whoever she worked with now knew Mara's face. At dawn she wrote a short list on the back of the shop receipt. Move the charm-focus out of the crate. Change shifts. Stop going straight from work to the tunnel. She had lost the follower for one night. She had not lost her. The heart above the plaza was still dark, and Mara was still the only person trying to light it, but from now on she would have to work as if watched.