“I’ve tried to teach her,” Sophie said.

Meredith snorted. “That’s like husbands teaching their wives to drive. Never try to teach your beloved anything technical. It’s the fast lane to divorce. Nah, Sophie, leave it to me. I’ll have her writing code by the end of the year.”

It had never gone that far, but Meredith had taught Lindsay more about hardware, software, hacking and net-surfing than she’d ever needed to use. The only question it had left unanswered was what exactly Meredith did for a living that meant she had all this stuff at her fingertips. There was no secret about who she worked for—a software and electronics complex in Silicon Valley, south of San Francisco, whose income, everyone knew, came from the Pentagon. Whenever Lindsay or anyone else asked for something approximating a job description, Meredith would simply smile and shake her head. “I kill bugs. You want more details, you have to need to know, babe,” she’d say. “And just being curious don’t count as a need.” Lindsay had sometimes wondered if even Penny had known.

Somehow, though, Meredith’s silence about that crucial area of her life hadn’t been a barrier between her and Lindsay. While Sophie was undoubtedly closer to Penny, Lindsay and Meredith forged a complicit bond where they played the childish role to the other pair’s sensible maturity, running off to play computer games or to chase the dog along the beach when the conversation grew too serious for their mood.

But it wasn’t all frivolity between them. Meredith regularly printed out obscure snippets and articles from the Internet that she thought might interest Lindsay, and often as they walked along the sand the two had debated the thorny issues around freedom of information and the preservation of personal privacy. From theoretical debate, their dialogues had moved to the personal, each sharing issues in their relationships with lovers, friends and colleagues. While Lindsay was unequivocal in her conviction that Sophie was her closest friend, she knew too that Meredith had an important place in her life. “I have to have somebody to whinge about Sophie to,” she’d said once, only partly joking. She might have few complaints about her partner, but she knew herself well enough to realize that the way to keep them in perspective was to release them to someone who could point out that she was over-reacting. For Meredith, coached in a life of secrecy both professionally and personally, talking to Lindsay, no matter how sparingly or obliquely, was often her only outlet. It wasn’t so surprising that she had sent Sandra Bloom after her.

Remembering what Meredith had taught her about the relentless logic of computers, Lindsay sifted through the little she knew about Penny’s death. She sighed and shifted in her seat. “How did the police get on to the idea that it wasn’t an accident after all?” she asked Sandra Bloom.

The detective looked up from her copy of Sense and Sensibility. “The murder method was identical to the one outlined in Ms. Varnavides’ new book,” she said, her tone patiently condescending.