She was told to draw only what she saw. This was the first rule of the workshop and the only one the master ever repeated, usually while standing behind her with his hands folded, so that she felt the rule more than heard it. What she saw was mostly coastline: the long grey shoulder of the bay, the two islands that looked like one from the tower and like three from the pier, the sandbar that came and went with a tide the fishermen swore by and the master swore at.

On the third day she saw a coastline that was not there the day before, and drew it anyway, because those were the instructions. It ran north from the lighthouse for perhaps a mile and then turned inland, as if it had changed its mind. She inked it carefully. She did not mention it at supper.

The master found it the next morning. He said nothing for a long time, which was worse than the things he usually said. Then he took the sheet to the window and held it against the light, as if the new coast might be a flaw in the paper rather than a flaw in the world.

"Where," he said at last. She told him. He looked north from the tower for the rest of the day and saw nothing, and that evening he told her to draw it again, from memory this time, and to change nothing. She did. The second drawing matched the first to the width of a hair. That night the master locked the map room, which he had never done, and she lay awake listening to a sea that seemed, for the first time, to be listening back.

On the fifth day the coast was there for everyone. Fishermen came up from the harbour to stand at the tower window and say that it had always been there, which was what people said about anything they could not explain. The master let them say it. He had the apprentice pin both drawings to the wall, dated, and he stood beside them with his hands folded and did not smile.

Then he gave her a new sheet, the largest in the stock, and told her to go north along the new shore and draw what she found at the end of it. He did not say what he expected. He did say she should take a lamp, and bread, and that she should not, whatever it looked like, draw anything she had not seen.