‘Elizabeth was shy and rather sad to begin with, but I made it my business to be so very kind to her and make her smile. We soon became the very best of friends. As she cried at nights, Mother arranged for her bed to be brought into my bedroom. Most nights, she crept into my bed, and we spent half of every night chattering away like birds. Elizabeth shared my lessons with my governess. We played in the grounds and took trips into the village. She was as close to me as a sister would be. But, you see, I knew that she was different. I was the only one who knew her secret.’ Mrs Hart looked up from Bertie. She spoke her next words slowly and precisely, giving weight to each. ‘One in, one out.’

Lou’s attention had drifted into Mrs Hart’s story, but at the sound of the familiar words, it snapped back to the cold attic. She wrapped her arms around her waist. Mrs Hart couldn’t possibly know how she had come to be here. Could she?

‘One in, one out?’ Lou said, reflecting Mrs Hart’s words back at her, hoping at the same time to sound innocent.

Mrs Hart smiled. ‘Elizabeth was a visitor like no other,’ she said. ‘She stayed with us for five years until the day she went out and never returned. A telegram arrived to notify us that she had met an old friend and, on the spur of the moment, had gone to stay with her. I should have been frantic with worry as Elizabeth had no friends that I was aware of. But I felt something. A shift is the only way I can describe it, as though a piece of the world had fallen into place.

‘A telegram arrived just weeks later saying that she had met a military man who had swept her off her feet. They were travelling to India where her future husband was stationed and where they would marry and settle. I knew that it simply wasn’t true. I knew that it must be this house’s way of accounting for Elizabeth’s return to wherever it was that she had come from. But that didn’t stop me from being distraught at the loss of my friend. My mother, on the other hand, was quite satisfied as marriage for Elizabeth was to be celebrated, and she had got it on good authority that Elizabeth’s husband was a respectable match. When I pushed her as to whose authority this was, she seemed unable to remember. The fact that I knew more than my mother made me accept my special connection to this house. Just as you must accept yours.’

Mrs Hart’s attention had wandered from Lou, but now, she caught her in her direct gaze again. Lou stared back, unable to speak.

‘When the telegram arrived announcing your arrival, Louisa, and it was from Elizabeth, I knew that you, just like her, were to be a special type of visitor.’