Heart padlock and key with butterflies on the back

The padlock came back to the workshop on Tuesday, carried in a grey cloth by the queen's own footman, who would not say who had sent it. Father set it on the bench under the north window and we both stared at it for a long while. It is a heart, cast in silver gone soft with handling, its keyhole hidden inside a nest of scrolls like a wren in brambles. Nobody in Calder has ever seen a lock so proud of itself.

The key was the trouble. Father made it four winters ago for the old king's wine cellar, and it was the finest thing he ever filed. Along its shaft he cut a line of Latin that curls like smoke, and when I asked what it meant he said only that a patient hand opens every door in the end. The footman said the queen wanted the key returned to the lock. Father turned it over in his fingers and said nothing for an hour, then went down to the cellar with a lamp and came back grey-faced. The cellar was walled up the spring the old king died. There was no door left for the key to open.

So we did the only sensible thing and opened the padlock instead. It gave with a sound like a held breath let go. Inside lay a folded square of paper, and three pale butterflies, dry as pressed leaves, that lifted and went out through the window before either of us could catch them. The paper held one line in the queen's careful hand: keep what you were made to keep.

I have hung the key on the nail beside the workshop door, where the morning light finds the scrolls. The padlock sits on the shelf above it, shut, with nothing inside. Write when the ships come in, and tell me whether the sea has butterflies too.

Your sister, Wren