Our neighbour Hatice keeps her spare key under a flat stone by the door. Everyone on the floor knows this. When she goes to her village in summer, we water her plants. When we travel, she feeds our cat. Nobody writes anything down. Last month a new family moved into the empty flat. The son saw me lift the stone. "Is that safe?" he asked. "Anyone can take it." I did not have a good answer. I said it had been there for twenty years. That night I could not sleep. Maybe he was right. In the morning I told Hatice. She listened and then laughed. "The key is not for thieves," she said. "It is for the day I fall in my kitchen and cannot reach the door." She put the stone back. Later I saw the new family's son outside her flat, watering the plants.