It wasn’t until they’d split up and started poking around the nooks and crannies of the hotel that Liza spotted the flaw with the groups-of-three plan. That flaw being that even though nobody was going to be alone with a murderer, if the murderer had a gun, that wouldn’t necessarily help. And if Mr Burgh was the killer—which seemed hard to rule out—then while Liza didn’t like to steer too hard into gender stereotypes, she wasn’t sure that the two of them could take him even if he was unarmed. Sure, Hanna was feisty, but she also weighed about six pounds and had a day job that didn’t involve lifting anything heavier than a manila folder full of share certificates. Liza was slightly taller and occasionally went jogging, but she wasn’t exactly a fighter either. Especially not since she’d chosen her footwear—currently a pair of high espadrille wedges with glittery ankle straps—for looking cute on holiday, rather than running away from serial killers.

Which meant that as they were searching the lounge—a room that was full of tiny cabinets and little nooks a hypothetical murderer could easily stash a weapon in—she kept glancing uneasily over her shoulder in a way that she was worried was becoming increasingly obvious. Mr Burgh almost certainly wasn’t the killer. But that was surprisingly little comfort when he was standing right behind her.

“Hey.” Hanna shifted a small bookshelf to reveal a small door, just visible, painted the same off-yellow colour as the walls.

“Ah.” Mr Burgh looked apologetic. “I don’t think that’s anything.”

Guilty evasive, Liza wondered, or bumbling evasive? “It looks like something,” she said.

“According to the plans it’s one end of an old secret passage,” he explained, “but it was bricked up years ago.”

“Where’s the other end?” asked Liza, not quite willing to let mysterious secret passage go without at least one follow-up question.

“The conservatory, I think.” Mr Burgh shrugged. “But I’m afraid we can’t get it open now.”

It didn’t seem worth forcing the issue, so Liza filed it away under weird things about the hotel and got back on with looking for a murder weapon. The search did not, in the end, reveal anything unusual. Either the killer had not been so foolish as to hide the murder weapon in the hotel, or they had hidden it well enough that three groups of amateur sleuths running on adrenaline and uncertainty couldn’t find it. At the very least it was in nobody’s room, which ruled out one quick and simple way of identifying the culprit. Or, Liza’s mind immediately added, the person the culprit was trying to frame.

Of course, Mrs Ackroyd had left early, and so if it had been her, she might have ditched the gun anyway.

She might, for example, have thrown it out of the window.