He stared back at the porch, and the handsome front door with its corroded brass lion’s-head knocker, and thought back, as he had several times, to that moment on Friday when he was standing there with his mother-in-law and had seen, fleetingly, that shadow. Trick of the light, or a removals man, or maybe some bird or animal – possibly the squirrel?

He went inside, through the atrium, and turned right into the kitchen. In the scullery beyond was a deep butler’s sink, a draining board and a wooden clothes-drying rack on a rope and pulley system to raise and lower it. There was also an ancient metal pump, fixed to the wall, for drawing water from the well that was supposedly under the house, but which no one had yet managed to find.

The cellar door, at the rear of the scullery, had an enormous, rusty lock on it, with a huge key, like a jailer’s. It was ajar. He went down the steep brick steps to see if the builders were OK and to tell them to help themselves to tea and coffee up in the kitchen, but they cheerily told him that they had their thermoses and were self-sufficient.

Then he climbed up the three flights of stairs to his chaotic office in the round tower on the west side of the house. It was a great space, about twenty feet in diameter, with a high ceiling, and windows giving fabulous views, one of them onto the steep, grassy slope of the hill rising out of sight. He waded through the unopened boxes and towers of files littering the floor, carefully stepping past a row of framed pictures stacked against a wall, reached his desk, and switched on his radio to Radio Sussex. As he heard the presenter grilling the Chief Executive of the Royal Sussex County Hospital over waiting times in A&E, his phone pinged with an incoming text.

It was from one of his two closest friends, Rob, asking if he fancied a long mountain bike ride round Box Hill next Sunday morning. He replied:

Sorry, mate, going to be spending time sorting out the house with Caro. And five acres of lawns to mow. Come over and see the place at the w/e.

He sent it and moments later the single-word reply pinged back.

Tosser.

He grinned. Rob and he had barely said a polite word to each other throughout their fifteen-year friendship. He sat down, retuned the radio to Radio 4, and logged on to his computer, checking his emails for anything urgent, then had a quick look at Twitter and Facebook, aware that he had not posted anything on either about the move yet. He also wanted to post some pictures of the worst dilapidations in the house on his Instagram page to show before and after. He and Caro had discussed approaching the TV show Restoration Man, but decided against because of wanting privacy.

But before any of that he had an urgent job to complete, and although the internet connection wasn’t great, it was working, sort of. His Apple Mac geek – as he jokingly referred to his computer engineer – was coming over that afternoon to try to sort it all out, but in the meantime he just had to get on with it, with an urgent deadline for a new client, the grandly titled Charles Cholmondley Classic Motors, Purveyors of Horseless Carriages to the Nobility and Gentry since 1911. They traded top-end classic and vintage sports cars, and had taken several large and very expensive stands at a classic car show that was looming up in Dubai, next month, and for next year’s Goodwood Festival of Speed. They needed an urgent revamp of their very dull and old-fashioned website.

If he got it right, it could open the door to the whole world of classic cars which he had always loved. He’d made a serious stash of cash from his previous website business, an innovative search site for people looking for properties. If he could repeat this success in the lucrative world of classic cars, they would be sorted. They’d have the money to do everything they wanted to this house.

He harboured doubts about the provenance of Charles Cholmondley Classic Motors, as the company had only been registered nine years ago. Its proprietor was a diminutive, self-important man in his fifties. On the two occasions when Ollie had met Charles Cholmondley himself, he had been flamboyantly dressed in a cream linen suit, bow tie and tasselled loafers, with silver hair that looked freshly coiffed. It was exactly the image of him that fronted the website, the dealer standing between a gleaming 1950s Bentley Continental and a Ferrari of similar vintage.

Personally, Ollie thought the message this gave off was, ‘Come and get royally screwed by me!’ He’d tried, subtly, to dissuade him from wearing the bow tie, but Cholmondley would have none of it. You have to understand, Mr Harcourt, that the people I am dealing with are very rich indeed. They like the feeling of dealing with their own kind. They see this bow tie and they see someone of distinction.

Something really did not smell right about Charles Cholmondley, and Ollie even wondered if this was his real name. But hey, he was paying good money, which at this moment he needed badly, both for this house and, if there was any surplus, to finish the restoration of his beloved Jaguar E-Type which was languishing in a lock-up in Hove until he could clear out enough space for it in one of the garages behind the house. At the moment, with all the work needed on the house, that Jag was going to be, unfortunately, a low priority.

Moments after he had settled down, Caro phoned to ask if the plumber had arrived to start work on their bathroom, and Ollie told her there’d been no sign of him yet.

‘Can you call him?’ she asked. ‘The bloody people were meant to start work at nine today.’

‘I will, darling,’ he said, trying not to sound irritated. Caro could never get her head around the fact that, although his office was based at home, he was actually working just as hard as she was. He dialled the plumber, left a message on his voicemail, then focused on his client’s website. The radio continued in the background; he listened to it all the time he was working, either Radio Sussex or Radio 4, and on Saturdays, after Saturday Live, he loved to listen to the football show, The Albion Roar, on Radio Reverb. When there was nothing on the radio he fancied, he tuned his computer to Brighton’s dedicated television station, Latest TV.

He began surfing the sites of other classic car dealers, and became frustrated, in minutes, with the slow and flaky internet connection. Several times during the next hour he shouted at the computer in anger, and wondered just how much of his life had been wasted waiting for the sodding internet. Then, at 10.30 a.m., he went downstairs to make himself a coffee.

He climbed down the steep, spiral staircase, walked a short distance along the first-floor landing, then went down the stairs to the hall, turned right and entered the oak-panelled atrium that was the anteroom to the kitchen. As he did so he saw Bombay and Sapphire both standing in the middle of the room, their hackles up, watching something.

He stopped, curious, wondering what it was. Their eyes were darting around, right then left, then up, then to the right again, in absolute synch, almost as if they were watching a movie. What were they looking at? He stood with them but could see nothing. ‘What is it, chaps?’

The cats continued to stand there, ignoring him, hackles still up, eyes still moving together, utterly absorbed.

‘What is it, chaps?’ he said again, watching them, watching their eyes. It was giving him the creeps.

Then suddenly they both howled, as if in pain, shot out of the room and disappeared along the hallway.

Deeply puzzled, he walked through into the huge kitchen. It had a low, oak-beamed ceiling, an ancient blue four-oven Aga, a twelve-seater oak refectory table which had come with the property, a pine dresser, rows of pine-fronted fitted shelves and a double sink with a large window above it looking out across the rear lawn and grounds.