“Who is Christopher?” Robin asked.

“Well—I don’t know whether I should say,” replied Fizzy. “But I suppose, if you—of course, he can’t have anything to do with it. It’s just Kinvara’s spite. She’s talking about Sir Christopher Barrowclough-Burns. Old friend of Torks’ family. Christopher’s a senior civil servant and he was that boy Mallik’s mentor at the Foreign Office.”

The lavatory was chilly and antiquated. As she bolted the door, Robin heard Fizzy striding back to the drawing room, doubtless to placate the angry Torquil. She looked around: the chipped, painted stone walls were bare except for many small dark holes in which the occasional nail still stuck out. Robin presumed Kinvara was responsible for the removal of a large number of Perspex frames from the wall, which now stood stacked on the floor facing the toilet. They contained a jumble of family photographs in messy collages.

After drying her hands on a damp towel that smelled of dog, Robin crouched down to flick through these frames. Izzy and Fizzy had been almost indistinguishable as children, making it impossible to tell which of them was cartwheeling on the croquet lawn, or jumping a pony at a local gymkhana, dancing in front of a Christmas tree in the hall or embracing the young Jasper Chiswell at a shooting picnic, the men all in tweeds and Barbours.

Freddie, however, was immediately recognizable, because unlike his sisters he had inherited his father’s protuberant lower lip. As white-blond in youth as his niece and nephews, he featured frequently, beaming for the camera as a toddler, stony-faced as a child in a new prep school uniform, muddy and triumphant in rugby kit.

Robin paused to examine a group shot of teenagers, all dressed head to toe in white fencing jackets, Union Jacks ran down the sides of everyone’s breeches. She recognized Freddie, who was standing in the middle of the group, holding a large silver cup. At the far end of the group was a miserable-looking girl whom Robin recognized immediately as Rhiannon Winn, older and thinner than she had been in the photograph her father had shown Robin, her slightly cringing air at odds with the proud smiles on every other face.

Continuing to search the boards, Robin stopped at the last one to examine the faded photograph of a large party.

It had been taken in a marquee, from what seemed to be a stage. Many bright blue helium balloons in the shape of the number eighteen danced over the crowd’s heads. A hundred or so teenagers had clearly been bidden to face the camera. Robin scanned the scene carefully and found Freddie easily enough, surrounded by a large group of both boys and girls whose arms were slung around each other’s shoulders, beaming and, in some cases, braying with laughter. After nearly a minute, Robin spotted the face she had instinctively sought: Rhiannon Winn, thin, pale and unsmiling beside the drinks table. Close behind her, half-hidden in shadow, were a couple of boys who were not in black tie, but jean and T-shirts. One in particular was darkly handsome and long-haired, his T-shirt bearing a picture of The Clash.

Robin got out her mobile and took a picture of both the fencing team and the eighteenth birthday party photographs, then carefully replaced the stack of Perspex boards as she had found them, and left the bathroom.

She thought for a second that the silent hall was deserted. Then she saw that Raphael was leaning up against a hall table, his arms folded.

“Well, goodbye,” said Robin, starting to walk towards the front door.

“Hang on a minute.”

As she paused, he pushed himself off the table and approached her.

“I’ve been quite angry with you, you know.”

“I can understand why,” said Robin quietly, “but I was doing what your father hired me to do.”

He moved closer, coming to a halt beneath an old glass lantern hanging from the ceiling. Half the lightbulbs were missing.

“I’d say you’re bloody good at it, are you? Getting people to trust you?”

“That’s the job,” said Robin.

“You’re married,” he said, eyes on her left hand.

“Yes,” she said.

“To Tim?”

“No… there isn’t any Tim.”

“You’re not married to him?” said Raphael quickly, pointing outside.

“No. We just work together.”

“And that’s your real accent,” said Raphael. “Yorkshire.”

“Yes,” she said. “This is it.”

She thought he was going to say something insulting. The olive dark eyes moved over her face, then he shook his head slightly.

“I quite like the voice, but I preferred ‘Venetia.’ Made me think of masked orgies.”

He turned and walked away, leaving Robin to hurry back out into the sunshine to rejoin Strike, who she presumed would be waiting impatiently in the Land Rover.

She was wrong. He was still standing beside the car’s bonnet, while Izzy, who was standing very close to him, talked rapidly in an undertone. When she heard Robin’s feet on the gravel behind her, Izzy took a step backwards with what, to Robin, seemed a slightly guilty, embarrassed air.

“Lovely to see you again,” Izzy said, kissing Robin on both cheeks, as though this had been a simple social call. “And you’ll ring me, won’t you?” she said to Strike.

“Yep, I’ll keep you updated,” he said, moving around to the passenger seat.

Neither Strike nor Robin spoke as she turned the car around. Izzy waved them off, a slightly pathetic figure in her loose shirt dress. Strike raised a hand to her as they took the bend in the drive that hid her from their sight.

Trying not to upset the skittish stallions, Robin drove at a snail’s pace. Glancing left, Strike saw that the injured horse had been removed from the field, but in spite of Robin’s best intentions, as the noisy old car lurched past its field, the black stallion took off again.

“Who d’you reckon,” said Strike, watching the horse plunge and buck, “first took a look at something like that and thought, ‘I should get on its back’?”

“There’s an old saying,” said Robin, trying to steer around the worst of the potholes, “‘the horse is your mirror.’ People say dogs resemble their owners, but I think it’s truer of horses.”

“Making Kinvara highly strung and prone to lash out on slight provocation? Sounds about right. Turn right here. I want to get a look at Steda Cottage.”

A bare two minutes later, he said:

“Here. Go up here.”

The track to Steda Cottage was so overgrown that Robin had missed it entirely the first time they had passed it. It led deep into the woodland that lay hard up against the gardens of Chiswell House, but unfortunately, the Land Rover was only able to proceed for ten yards before the track became impassable by car. Robin cut the engine, privately worried about how Strike was going to manage a barely discernible path of earth and fallen leaves, overgrown with brambles and nettles, but as he was already getting out, she followed suit, slamming the driver’s door behind her.

The ground was slippery, the tree canopy so dense that the track was in deep shade, dank and moist. A pungent, green, bitter smell filled their nostrils, and the air was alive with the rustle of birds and small creatures whose habitat was being rudely invaded.

“So,” said Strike, as they struggled through the bushes and weeds. “Christopher Barrowclough-Burns. That’s a new name.”