Lucy glanced at Finn. His jaw was rigid, a muscle working in his cheek. “You told Marilynne that Charlie had found a book there that linked Robert Catesby to the Order of the Knights Hospitaller,” he said.

Persis nodded sadly. “After that it was a whole new obsession with her,” she said. “She had Gabe digging around for all sorts of information on the Knights although she didn’t tell him why—” She gave her brother a glance that was half scornful, half affectionate. “Set Gabe off with anything like that and he’ll run like clockwork, no questions asked.”

“I thought she wanted inspiration for one of her art projects,” Gabriel said, looking even more sulky.

“Aunt M wanted me to get hold of the book,” Persis said, “but the curator hadn’t been at Chastleton when we visited and they wouldn’t lend it out without her agreement. Charlie was going to go back, but then I...” Her voice faltered. “I did something really stupid. I see that now.” She pushed her hair back from her face. “He was all excited about the things he was discovering and I was happy for him and...” She looked up. “I wanted to be a part of it. So I showed him a key that Aunt Marilynne had taken from the museum. It had been in the cabinet with the other finds from the site but she was certain it had some significance so she purloined it one day when Gabe wasn’t looking.” She gulped down some more of her tea. “When Charlie saw it, it immediately reminded him of something he’d seen at Chastleton. A box, or something. I told Aunt M later that day...” She stopped.

“And that night Charlie was killed,” Finn finished softly.

“I hoped it was just a coincidence,” Persis said. “I mean, Aunt M never said anything about what happened to me and I didn’t ask, but I sort of just knew.” She shuddered. “And one day, after Charlie’s accident when I was crying, she just said it had been for the best. That the treasure could now be hers as had been meant all along.”

“But there is no treasure,” Gabriel said plaintively. “I’ve been telling everyone that all along.”

“The woman who saw Catherine Catesby’s ghost says there was,” Persis said, “at least that’s what Aunt M told me.”

“It doesn’t really matter whether there was or not if you believe it,” Lucy said. “And Marilynne evidently did.” She turned to Persis. “Why didn’t she simply go along to Chastleton and take the box, or whatever it was, after Charlie died?” she asked.

“She didn’t know exactly what it was or where to find it,” Persis said unhappily. “She kept badgering me about it, but I couldn’t remember. She was so angry with me! And the police were sniffing around and people were talking. I think she got scared and thought she’d wait awhile. But then you came back, Finn, when we all thought the project would be abandoned, and Lucy arrived and seemed to be following up on all Charlie’s research. She tried to scare you off but it didn’t work.”