She had caught sight of the historical marker only because she'd gone back, deliberately, to Lake Invera-rity one day, owing to this, what you might have to call, growing obsession, with "bringing something of herself" -even if that something was just her presence-to the scatter of business interests that had survived Inverar-ity. She would give them order, she would create constellations; next day she drove out to Vesperhaven House, a home for senior citizens that Inverarity had put up around the time Yoyodyne came to San Narciso. In its front recreation room she found sunlight coming in it seemed through every window; an old man nodding in front of a dim Leon Schlesinger cartoon show on the tube; and a black fly browsing along the pink, dandruffy arroyo of the neat part in the old man's hair. A fat nurse ran in with a can of bug spray and yelled at the fly to take off so she could kill it. The cagy fly stayed where it was. "You're bothering Mr Thoth," she yelled at the little fellow. Mr Thoth jerked awake, jarring loose the fly, which made a desperate scramble for the door. The nurse pursued, spraying poison. "Hello," said Oedipa.

"I was dreaming," Mr Thoth told her, "about my grandfather. A very old man, at least as old as I am now, 91. I thought, when I was a boy, that he had been 91 all his life. Now I feel," laughing, "as if I have been 91 all my life. Oh, the stories that old man would tell. He rode for the Pony Express, back in the gold rush days. His horse was named Adolf, I remember that."

Oedipa, sensitized, thinking of the bronze marker, smiled at him as granddaughterly as she knew how and asked, "Did he ever have to fight off desperados?"

"That cruel old man," said Mr Thoth, "was an Indian killer. God, the saliva would come out in a string from his lip whenever he told about killing the Indians. He must have loved that part of it."

"What were you dreaming about him?" "Oh, that," perhaps embarrassed. "It was all mixed in with a Porky Pig cartoon." He waved at the tube. "It comes into your dreams, you know. Filthy machine. Did you ever see the one about Porky Pig and the anarchist?"

She had, as a matter of fact, but she said no. "The anarchist is dressed all in black. In the dark you can only see his eyes. It dates from the 1930's. Porky Pig is a little boy. The children told me that he has a nephew now, Cicero. Do you remember, during the war, when Porky worked in a defense plant? He and Bugs Bunny. That was a good one too."

"Dressed all in black," Oedipa prompted him.

"It was mixed in so with the Indians," he tried to remember, "the dream. The Indians who wore black feathers, the Indians who weren't Indians. My grandfather told me. The feathers were white, but those false Indians were supposed to burn bones and stir the boneblack with their feathers to get them black. It made them invisible in the night, because they came at night. That was how the old man, bless him, knew they weren't Indians. No Indian ever attacked at night. If he got killed his soul would wander in the dark forever. Heathen."

"If they weren't Indians," Oedipa asked, "what were they?"

"A Spanish name," Mr Thoth said, frowning, "a Mexican name. Oh, I can't remember. Did they write it on the ring?" He reached down to a knitting bag by his chair and came up with blue yam, needles, patterns, finally a dull gold signet ring. "My grandfather cut this from the finger of one of them he killed. Can you imagine a 91-year-old man so brutal?" Oedipa stared. The device on the ring was once again the WASTE symbol.

She looked around, spooked at the sunlight pouring in all the windows, as if she had been trapped at the centre of some intricate crystal, and said, "My God."

"And I feel him, certain days, days of a certain temperature," said Mr Thoth, "and barometric pressure. Did you know that? I feel him close to me."

"Your grandfather?"

"No, my God."

So she went to find Fallopian, who ought to know a lot about the Pony Express and Wells, Fargo if he was writing a book about them. He did, but not about their dark adversaries.

"I've had hints," he told her, "sure. I wrote to Sacramento about that historical marker, and they've been kicking it around their bureaucratic morass for months. Someday they'll come back with a source book for me to read. It will say, 'Old-timers remember the yam about,' whatever happened. Old-timers. Real good documentation, this Californiana crap. Odds are the author will be dead. There's no way to trace it, unless you want to follow up an accidental correlation, like you got from the old man."

"You think it's really a correlation?" She thought of how tenuous it was, like a long white hair, over a century long. Two very old men. All these fatigued brain cells between herself and the truth.

"Marauders, nameless, faceless, dressed in black. Probably hired by the Federal government. Those suppressions were brutal."

"Couldn't it have been a rival carrier?"

Fallopian shrugged. Oedipa showed him the WASTE symbol, and he shrugged again.

"It was in the ladies' room, right here in The Scope, Mike."

"Women," he only said. "Who can tell what goes on with them?"

If she'd thought to check a couple lines back in the Wharfinger play, Oedipa might have made the next connection by herself. As it was she got an assist from one Genghis Cohen, who is the most eminent philatelist in the L.A. area. Metzger, acting on instructions in the will, had retained this amiable, slightly adenoidal expert, for a percent of his valuation, to inventory and appraise Inverarity's stamp collection.

One rainy morning, with mist rising off the pool, Metzger again away, the Paranoids off somewhere to a recording session, Oedipa got rung up by this Genghis Cohen, who even over the phone she could tell was disturbed.

"There are some irregularities, Miz Maas," he said. "Could you come over?"

She was somehow sure, driving in on the slick freeway, that the "irregularities" would tie in with the word Trystero. Metzger had taken the stamp albums to Cohen from safe-deposit storage a week ago in Oedipa's Impala, and then she hadn't even been interested enough to look inside them. But now it came to her, as if the rain whispered it, that what Fallopian had not known about private carriers, Cohen might.

When he opened the door of his apartment/office she saw him framed in a long succession or train of doorways, room after room receding in the general direction of Santa Monica, all soaked in rain-light. Genghis Cohen had a touch of summer flu, his fly was half open and he was wearing a Barry Goldwater sweatshirt also. Oedipa felt at once motherly. In a room perhaps a third of the way along the suite he sat her in a rocking chair and brought real homemade dandelion wine in small neat glasses.

"I picked the dandelions in a cemetery, two years ago. Now the cemetery is gone. They took it out for the East San Narciso Freeway."

She could, at this stage of things, recognize signals like that, as the epileptic is said to-an odor, color, pure piercing grace note announcing his seizure. Afterward it is only this signal, really dross, this secular announcement, and never what is revealed during the attack, that he remembers. Oedipa wondered whether, at the end of this (if it were supposed to end), she too might not be left with only compiled memories of clues, announcements, intimations, but never the central truth itself, which must somehow each time be too bright for her memory to hold; which must always blaze out, destroying its own message irreversibly, leaving an overexposed blank when the ordinary world came back. In the space of a sip of dandelion wine it came to her that she would never know how many times such a seizure may already have visited, or how to grasp it should it visit again. Perhaps even in this last second-but there was no way to tell. She glanced down the corridor of Cohen's rooms in the rain and saw, for the very first time, how far it might be possible to get lost in this.