The two worlds on either side of the door couldn’t have been more different. Where the ladies’ corridor was hung with red striped wallpaper (faded now to soft rose and claret), the walls in the nursery wing were painted: hard, shiny brown on the lower half where grubby fingers could reach, cream above. There were no gilt-framed portraits here. Cleaner squares on the scuffed paintwork showed where pictures had once hung, though for the most part they had been taken down. Only one remained, hanging crookedly in a broken wooden frame.

Jem paused as he passed it. It was a print of a golden-haired little girl in white-frilled petticoats holding a basket of kittens, but its Victorian sentimentality was somewhat marred by the rash of pale scabs that appeared to have broken out on the child’s face. He lifted a hand to run his fingers over the dusty glass.

‘Wet paper pellets, apparently,’ Kate said, answering the question before he asked it. ‘Fired through a straw. You find them all over the place in the nursery wing.’

‘Randolph Hyde?’

‘Who else?’

She continued along the corridor and heard his exhalation of impatience and disgust as he followed.

‘I’ve never been in this part of the house before.’

‘Not many people have. It’s been closed up for years.’

‘Since he and his sister were children?’

‘Not quite that long. When Sir Randolph and Lady Etchingham left the nursery and the last nanny moved out, it was used for visiting servants when the family had house parties.’ She stopped beside the last door and opened it. ‘See?’

It was a large, square room, and with no furnishings or carpet to be damaged by the sun, its shutters had been left open. The last of the day’s light fell on the collection of thin, straw-stuffed mattresses that were haphazardly piled on the dusty floor and leaned against its flaking walls.

She’d expected him to glance in without much interest, but he stepped past her. Going across to a few lumpy pallet mattresses that were stacked against the walls, he began moving them with his free hand, examining them as if he was looking for something on their stained canvas covers.

‘Did they have a lot of parties?’

‘Not by the standards of many houses; this place is too inconvenient for guests to get to. But Sir Randolph has always been a great one for parties, so I believe when he was at Cambridge the house would be filled with his friends for long stretches in the holidays—much to Sir Henry’s disapproval. Apparently when Randolph entertained, it was always on rather an epic scale. I understand that was why Sir Henry sent him to India, in the hope that a job would make him mend his wild ways.’

She was talking too much, trying to smooth over the earlier awkwardness and compensate for her nervousness at being with him like this, the two of them alone in the vast house, with the day dying away to an echo outside.

Jem let the mattress he was holding fall back onto the others, raising a cloud of dust and a waft of musty straw.

‘And did it?’

‘No. Quite the opposite, I believe. But it removed the problem from Coldwell. Mostly, anyway. On the rare occasions he came home I think it was worse than ever. He used to get together with his old Cambridge friends here. Apparently the parties used to get rather out of hand.’

‘In what way?’

‘I don’t know exactly… Mrs Walton was too loyal to gossip, but she was getting a little confused by the time I knew her. Sometimes she used to say things without realising, as if she’d forgotten she was speaking out loud.’

‘What sort of things?’

‘Oh—I don’t know… She’d mutter under her breath about young Mr Hyde’s sins finding him out, and God knowing the secrets of our hearts, that sort of thing. She was very devout, and very loyal to Sir Henry—like Mr Goddard—but that loyalty didn’t extend to Randolph. She barely bothered to hide her disapproval of him. When I first arrived, they were very short-staffed, and I always got the impression that she blamed him for servants leaving. If it was because he’d been inappropriate with the maids, I think she would have said…’ She gave an awkward laugh. ‘Perhaps he brought ladies of ill repute here or something. I suppose that would explain why those pages were removed from the visitors’ book, wouldn’t it?’

The light was almost completely gone now, and the room was full of shadows, making everything melt into the dusk. She could see the outline of Jem’s shoulders against the window, but it was impossible to see his face or read its expression.

‘Did Mrs Walton keep records? Of visitors and their servants—that kind of thing? If so, you could find out who was here when those pages were removed.’

‘Her bookkeeping was very erratic, especially by then—much to Mr Fortescue’s exasperation. She always said she held all the information she needed in her head, but that got rather erratic too. Poor Mrs Walton… Her mental decline must have been underway already, but it became quite rapid after I started.’

It was through helping her with the figures, keeping track of invoices, and taking charge of paying bills that Kate—for all her youth, inexperience, and ‘borrowed’ character—had learned the responsibilities of a housekeeper and been in a position to take over. But she didn’t want to admit that to Jem Arden, who had a habit of drawing too much out of her as it was. Her keys chimed softly as she straightened up. ‘We’d better go, before it gets too dark to see.’

She went ahead of him down the stairs, holding up her skirts and treading carefully so she didn’t miss her footing in the gloom. Outside the air was soft, scented with summer. She waited as he locked the door with one of the giant keys on the ring Mr Goddard had given him, and they walked back, along the side of the house, beneath the shuttered windows of the library and the billiard room. The tower on the hill looked like an illustration from a child’s storybook against the pink-streaked sky. A single star glinted above its turreted roofline.

Back inside the familiar below-stairs world, the silence lay heavily over everything, like the dust sheets upstairs. Mr Goddard hadn’t lit any lamps, and the blue dark was scented with roses. In the corridor outside the butler’s pantry and the footmen’s wardrobe Jem stopped.

‘I’ll say good night, then.’

‘You’re sleeping down here?’