Siobhan was studying the board again, probing the schematic for flaws. “So what happened to Ben?” she asked at last.

“I can tell you what I think…”

“Go on then.” She folded her arms.

“Guards at the castle thought there was an intruder. My guess is, it was Stacey. She knew her brother was there and was bursting to tell him. We’d found the patch-she’d probably heard about that from Steelforth. Thought it was time to share news of her exploits with her brother. As far as she was concerned, Guest’s death meant closure. And, by Christ, she’d made sure he paid for his crimes-mutilating his body. She relishes the challenge of sneaking past the guards. Maybe she’s sent him a message, so he comes out to meet her. She tells him everything-”

“And he offs himself?”

Rebus scratched the back of his head. “I think she’s the only one who can tell us. In fact, if we play it right, Ben’s going to be crucial in getting a confession. Think how hellish she must be feeling-that’s her whole family gone now, and the one thing she thought would bring her and Ben closer together has actually destroyed him. And it’s all her fault.”

“She did a pretty good job of hiding it.”

“Behind all those masks she wears,” Rebus agreed. “All these warring sides to her personality…”

“Steady,” Siobhan warned. “You’re starting to sound like Gilreagh.”

He burst out laughing, but stopped just as abruptly and scratched at his head again, eventually running the hand through his hair. “Do you think it holds up?”

Siobhan puffed out her cheeks and exhaled loudly. “I need to give it a bit more thought,” she conceded. “I mean…scrawled on a board like this, I can see it makes a kind of sense. I just don’t see how we’ll prove any of it.”

“We start with what happened to Ben…”

“Fine, but if she denies it, we’re left with nothing. You’ve just said so yourself, John, she wears all these masks. Nothing to stop her slipping one on when we start asking about her brother.”

“One way to find out,” Rebus said. He was holding Stacey Webster’s business card, the one with her cell number.

“Think for a minute,” Siobhan counseled. “Soon as you call her, you’re giving her advance warning.”

“Then we go to London.”

“And hope Steelforth lets us talk to her?”

Rebus considered for a moment. “Yes,” he said quietly, “Steelforth…Funny how quickly he knocked her back to London, isn’t it? Almost as if he knew we were getting close.”

“You think he knew?”

“There was surveillance video at the castle. He told me there was nothing to see, but now I’m wondering.”

“There’s no way he’s going to let us go public,” Siobhan argued. “One of his officers turns out to be a killer and might even have done away with her own brother. Not exactly the PR he’s looking for.”

“Which is why he might be willing to do a deal.”

“And what exactly have we got to offer?”

“Control,” Rebus stated. “We step back and let him do it his way. If he turns us down, we go to Mairie Henderson.”

Siobhan spent the best part of a minute considering the options. Then she saw Rebus’s eyes widen.

“And we don’t even have to go to London,” he told her.

“Why not?”

“Because Steelforth’s not in London.”

“Then where is he?”

“Under our bloody noses,” Rebus explained, starting to wipe the board clean.

By which he meant: an hour’s rapid drive to the west.

They spent the whole trip going through Rebus’s theory. Trevor Guest hightailing it out of Newcastle-maybe owing money on some deal. Quick route to the handily anonymous border country. Scratches around, but can’t find a fix and hasn’t any money. His one area of expertise: burglary. But Mrs. Webster is home, and he ends up killing her. Panics and flees to Edinburgh, where he assuages his guilt by working with the elderly, with people like the woman he murdered. Not sexually assaulted-he liked them a lot younger.

Meanwhile-Stacey Webster is destroyed by her mother’s murder, heartbroken when the death destroys her father too. Using her detective’s skills to track down the likely culprit, only he’s already behind bars. But due out soon. Giving her time to plan her revenge. She’s found Guest on BeastWatch, alongside others like him. She picks her targets geographically-easy reach of her Midlands base. Her counter culture existence gives her access to heroin. Does she get Guest to confess before she murders him? It doesn’t really matter: by then she’s already killed Eddie Isley. Adds one more, to reinforce the notion that a serial killer is at large, then stops. Sated and at peace. Far as she’s concerned, she’s been cleaning scum off the streets. SO12’s G8 planning has led her to the Clootie Well, and she knows it’s the perfect spot. Someone will happen upon it. And they’ll spot the clues. To be certain, she ensures they have one name straightaway…the only name that matters.

No way she’s going to be found.

The perfect crime.

Nearly…

“I have to admit,” Siobhan said, “it sounds plausible.”

“That’s because it’s what happened. Thing about the truth, Siobhan: it almost always makes sense.”

They made good time along the M8, and got onto the A82. The village of Luss was just off the main road on the western shore of Loch Lomond.

“They used to film Take the High Road here,” Rebus informed his passenger.

“One of the few soaps I’ve never watched.”

Cars were crawling past them on the other side of the road.

“Looks like play’s finished for today,” Siobhan commented. “Might have to come back tomorrow.”

But Rebus wasn’t about to concede defeat. Loch Lomond Golf Club was a members-only facility, and the arrival of the Open had brought with it extra security. There were guards on the main gate, and they checked both Rebus’s and Siobhan’s ID carefully before phoning on ahead, during which time a mirror on a long stick was played along the length of the car’s undercarriage.

“After Thursday, we’re taking no chances,” the guard explained, handing back their badges. “Ask at the clubhouse for Commander Steelforth.”

“Thanks,” Rebus said. “By the way…who’s winning?”

“It’s a tie-Tim Clark and Maarten Lafeber, fifteen under. Tim shot six under today. Monty’s nicely placed though-ten under. Be a great game tomorrow.”

Rebus thanked the guard again and put the Saab into gear. “Did you catch any of that?” he asked Siobhan.

“I know Monty means Colin Montgomerie.”

“Then you’re every bit as well informed about the royal and ancient game as I am.”

“You’ve never tried?”

He shook his head. “It’s those pastel sweaters…I could never see myself wearing one.”

As they parked and climbed out, half a dozen spectators walked past, discussing the day’s events. One wore a pink V-neck, the others yellow or pale orange or sky blue.

“See what I mean?” Rebus said. Siobhan nodded her agreement. The clubhouse was Scots baronial and called Rossdhu. There was a silver Mercedes parked up alongside, the chauffeur snoozing in the front seat. Rebus remembered him from Gleneagles-Steelforth’s designated driver.

“Cheers, Big Man,” he said, raising his eyes to the heavens.

A short, bespectacled gent with a highly developed mustache and sense of his own importance was striding out of the building toward them. All manner of laminated passes and ID cards were strung around his neck, clacking together as he moved. He barked out a word that sounded like Sekty but Rebus chose to translate as Secretary. The bony hand that shook Rebus’s was trying too hard. But at least he got a handshake; Siobhan might as well have been a shrub.

“We need to speak to Commander David Steelforth,” Rebus explained. “I doubt he’s the type to rub shoulders with the unwashed masses.”

“Steelforth?” The secretary took off his glasses and rubbed them against the sleeve of his crimson sweater. “Could he be corporate?”