Stepping into the hidden stairwell, with its stone steps, felt like stepping into a refrigerator. Even the wooden handrail was cool to the touch. Lou carefully picked her way up in the dark. The booze flowing around her system made her legs wobble, and she was so busy trying not to trip that she only realised where she was when she emerged from the stairwell at attic level.

Milky moonlight from a single window in the slanted eaves vaguely lit the bare walls and floors. How would she explain her presence if she was caught snooping around the quarters of the male staff in the dead of night? Picturing the faces of Bainbridge and Mrs Moriarty, she was on the verge of heading back down the stairs, when the knocking grew louder. How could the footmen and kitchen porters behind the closed doors sleep through that racket? They were no doubt dog-tired after a hard day’s graft. And here she was, about to make the floorboards creak as she crept through their world. OK. Right. You’re doing this for them, she told herself. So they can get a good night’s sleep.

Passing the window in the eaves, she noticed wisps of cloud hanging motionless in the still night sky. If there was no storm brewing outside, why was that bloody window knocking so fiercely in the room at the end of the corridor? A chill – which had nothing to do with the temperature of the air – raced down Lou’s spine. She tried, and failed, to shake it off. This was stupid. She should go down to her room, bury her head under the pillow and wait until morning.

She turned around. Her long shadow was there on the wall to meet her. She jumped, and her heart felt like it was about to explode out of her throat. The knocking grew in pace. It seemed to be demanding her attention. OK. Get a grip, Lou. This is stupid. It’s a window knocking, that's all. She turned back towards the lumber room to find that the door now stood open. A light shone from within. A shadow moved back and forth, back and forth, lengthening and shortening on the bare floorboards. Lou backed away. The shadow began to move more quickly, and with each step she took away from the lumber room, the noise grew louder. She looked along the corridor. It was further to go back than she had come, and it would take just one of the men to stick his head out of his room and she would have some serious explaining to do. There was no choice. She made her way quicker than she wanted to towards the light, all the while telling herself that there was a perfectly logical explanation for a door opening on its own – it’s the wind, it has to be the wind. But what wind?

Concentrating on putting one foot in front of the other, she reached the open door. She stood absolutely still, her eyes fixed on the floor, her heart battering her insides while the shadow swung like a pendulum across the floorboards. OK, now. She looked up. And in that instant, her fear evaporated.