“I know that-it was hard to miss them on the dance floor last night. But I tried her mobile, too, and it went right into voice mail, and you know she never lets anything stop her from taking a call, no matter where she is. And there’s something else. Do you know if she tried to reach you?”

“I didn’t see any calls or messages from her. Why?”

“This is what started me worrying in the first place. I have a strange text on my phone. It was sent shortly after midnight from a number I don’t recognize, one with a San Francisco area code. I tried to call the number back, but it only rings and rings before going into an automated voice mail.”

“So?” I still wasn’t sure what all the fuss was about. “It was probably just somebody’s mistake.”

“I don’t think it was a mistake, Rachel. The message says SOS.”

“Oh,” I said, the smile fading from my lips.

There are couples who have signals they use to communicate privately with each other in public venues. Fiddling with an earring could mean “I’m ready to leave” while adjusting a shirt cuff could be a warning to stay away from the salmon puffs. My friends and I developed a similar set of signals when we were in college, but SOS was the one we used most frequently. It was easy to form the letters in sign language with one hand by making a fist for the first S, opening the fist into a circle for the O, and then closing it again for the second S. This could be done discreetly, with your hand at your side or even, with enough practice, while holding a drink.

I’d found it to be an especially useful tool at social events when cornered by an ex-boyfriend or someone I would never want to be my boyfriend, ex or otherwise. I would give the signal, and soon one of my friends would arrive at my side, claiming an urgent need to speak to me privately. It might not have been terribly mature, but it was effective. Of course, usually Hilary had been the one doing the rescuing rather than requiring rescue; given her lack of adherence to social norms, she’d never had trouble extricating herself from uncomfortable situations without assistance. For her to use this signal at all was remarkable, and in the context of her unexplained absence, it was definitely cause for alarm.

“Did you check with Jane and Emma?” I asked. “Could one of them have sent it?”

“It would have been three in the morning on the East Coast, but I checked with them anyhow,” said Luisa. “And they didn’t know anything. So it had to be Hilary. Did you get anything similar?”

“Let me take a closer look at my messages,” I told Luisa. I put the call on hold and started scrolling through the log again.

“What’s wrong?” Peter asked. He’d ended his own call with Abigail and had picked up on my change in tone.

“I’m not sure yet,” I told him, studying the BlackBerry screen. There were the several missed calls from Luisa beginning around nine-thirty. Under those, with a time stamp of twelve-nineteen, was a text message from an unfamiliar number with a San Francisco area code. I clicked it open.

“SO” it read.

That was it. Just the S and the O. As if its sender had been interrupted before she’d had a chance to finish what she wanted to say.

And when Hilary had something to say, she didn’t leave it unsaid. At least, not by choice.

I flipped back to Luisa. “We’ll be right there,” I told her.

On the one hand, there had been some talk about mountain biking, so I was glad to have a valid reason to avoid yet another exercise-based outing. On the other hand, normal people didn’t have friends who suddenly went missing, potentially in the company of velvet-clad Internet tycoons. If anything, those were the sort of friends with whom an idiosyncratic person would surround herself.

“It’s no problem,” Peter assured me. “We can go biking later. We’ll just tell my parents we need to track Hilary down first.”

“Maybe we shouldn’t tell them about Hilary.”

“Why not?”

“I wouldn’t want them to worry unnecessarily,” I said, which he seemed to accept, but mostly I didn’t want to confide in him my concerns about not fitting in with his family. After all, normal people don’t worry about not being normal.

I insisted we live up to my promise to do the dishes, so we hurriedly loaded the dishwasher before going out on the deck, where we found Susan doing the crossword puzzle and Charles reading a book in the watery sunlight that passed for summer in San Francisco. Spot, curled by Susan’s feet, thumped his tail. Peter made our excuses about mountain biking, saying we were sore after the run-which was entirely true in my case-and had decided to catch up with friends instead.

“Is it all right to take the car?” he asked. The simple question made me feel as if we were teenagers up to something illicit, but his parents readily agreed without extracting any promises about not drinking and driving or reminders about curfews. There was some discussion of which hybrid to take, since the Forrests were a two-hybrid family, but that was easily resolved.

Susan turned to me. “Rachel, I think the Tiffany’s in Union Square is open this afternoon. It might be fun to swing by later and get started on registering you two. What do you think?”

I thought Peter’s family specifically and normal people more generally had peculiar ideas about what constituted fun. While I knew that brides-to-be were supposed to squeal with excitement over china patterns and place settings, I personally didn’t see the appeal, nor had I ever been much of a squealer. However, that didn’t seem to be the appropriate response. “Tiffany’s does sound like fun,” I said. Peter gave me yet another perplexed look, but I ignored him.

“How about three o’clock? Will that give you enough time with your friends?” Susan asked.

I certainly hoped so. If anyone was capable of getting herself into a deep fix, I was all too aware it was Hilary-she was uniquely skilled in this area. If we weren’t able to find her within a few hours, I couldn’t even begin to imagine what sort of trouble she might have encountered.

“That should give us plenty of time,” I told Susan, trying to sound more confident than I felt. “We’ll see you then.”

“Are you sure?” asked Peter as he followed me out the door.

“About registering at Tiffany’s or about finding Hilary by three o’clock?”

“Either. Both.”

“As sure as I’ll ever be,” I said. Which turned out to be entirely true.

5

As Peter steered the Prius up one hill and down another, I tried the number from the text message, letting it ring well after most phones go into voice mail or disconnect. Eventually an automated voice came on, inviting me without enthusiasm to leave a message. I explained I was looking for Hilary and left my own number. Then I replied to the text message for good measure, sending along the same information.

Traffic was light, and we even found parking on Market Street right across from the entrance to the Four Seasons hotel. We took one elevator up to the main lobby and then another elevator up to Luisa’s suite. She believed in traveling in style, and she had the wherewithal to support it, which worked out nicely for her. Ben and Hilary were staying in a more modest room at the same hotel, which would have been a stretch for a government employee and a journalist, but Hilary’s magazine assignment was covering her travel expenses.

Luisa greeted us at the door, and I remembered belatedly that she wasn’t even supposed to be here still. She’d mentioned the day before that her plane home was leaving at an “ungodly” hour, so she should have been gone long before she’d called to alert us to Hilary’s missing status. “Didn’t you have an early flight this morning?” I asked.

The question had barely left my mouth when something remarkable occurred: Luisa blushed.