Chapter 3 The Signal Rock

Dawn came flat and gray, the way all mornings come after a disaster: as if the sun were embarrassed to look. Juna woke in the tower base with her wetsuit half-dry and stiff, her neck sore from sleeping against a crate. Omar was already at the radio, a fresh battery bar glowing on the display. He had been up for hours. His notebook—a paper ledger rescued from the shed's office—was open, covered in a tight, precise hand. "Chart," he said without looking up. "The signal ran again. Midnight to four. Three beats, pause, three beats, pause. On the hour, every hour, plus an extra burst at 0358." "The same channel?" "Same frequency, same width of signal, same location. It's not a coincidence and it's not fishing floats." He turned the page. On it he had drawn a timeline: vertical lines for every burst he'd logged, each one thirty seconds long, each touching the gridline at exactly the same fractional point. "Every hour on the hour except one early burst. Whatever is sending this, it runs on a clock." "What kind of clock runs in water?" "That's the question I can't answer yet. But the burst at 0358—that one was different. Longer. The needle held at full deflection for almost a minute. Whatever it sends normally, it amplified that once." Juna pulled on her fins and buckled her knife belt. "Keep logging. I'm going to the school." "The school?" "The ridge. If anyone in this town survived with a radio, it's the hill. There could be hundreds of people up there, and not one of them can hear this tower." She hesitated at the door. "If the second wave comes, the school is the assembly point. They built it on the evacuation route." Omar examined her with the same attention he gave his instruments. "You're going to swim out of the drowned town, climb a ridge, walk a few miles, and come back here—in a day?" "Less, if I'm fast. The ridgeline road follows the hill above the flood line. I'll be walking, not swimming, most of the way." "Then watch the tide table, not the road." He tore a page from the ledger and pushed it at her. "I rebuilt the timing from the harbor master's tide charts before the water took them. You know how tsunami runup behaves in this bay—the big water follows the drowning tide down. If the surge comes again, it will come in the window I've marked. If you're not on high ground by then, you swim for the nearest roof." Juna read the marks, folded the paper, and pressed it into the dry pocket of her wetsuit. "Fast as I can." She left at dawn and came back at noon, and the news was better than she had dared to hope. The school on Cathedral Ridge had held. Thirty-one people had found their way there overnight—a school secretary who'd stayed to close the gym, the gym teacher, two families from the row houses on Fourth Street, and a bus driver who had pulled his route off the highway at the first tremors. They had water from the building's roof tanks, food from the cafeteria stores, and a working landline that no longer connected to anything. They had been listening to the same hiss Juna and Omar were, on a battery radio, since the grids went down. "Nobody's coming up the hill tonight," Juna reported. "I told them to stay put, ration the water, and keep a watch on the tide line. I told them about you and the tower." "And the signal?" "Not yet. They can't hear it on their receiver. It's local to us—to this reach of water." She peeled off her fins, sat down heavily on the paint crate, and drank from the water bottle Omar handed her. "You got more chart?" He had. Two new pages of it. Signal Rock pattern, he had labeled it at the top, and beneath, a diagram of the old channel. Signal Rock, he reminded her, was the stump of a sea stack that had once held the first Tidefall light. In 1911 the original lighthouse was abandoned when the harbor grew too big for it, and in 1946 the structure was torn down to its base and rebuilt on the point. The rock itself was blasted to a smooth shelf four feet below datum, marked by a spar buoy for the fishing fleet. It sat exactly at the mouth of the channel, the last land a hull scraped on the way to open water. He had drawn the bathymetry from memory—an old harbor survey he'd studied during the assessment. The rock dropped off sharply on its south side, in a trench that bottomed out at forty fathoms a mile from shore. "Here's what changes things," he said, tapping the drawing. "The signal is strongest at the moment of high tide. Every burst I logged this morning came at the top of a tide cycle or within a minute of it. When the water stands highest over Signal Rock, the transmitter is loudest. That means it's physically under water, and the deeper the water over it, the clearer we hear it." "Or it means it's tied to the same mechanism as the tide," Juna said. "Or that." Omar flipped to the last page. "And this is the thing I don't like." He had transcribed the midnight sequence as a row of characters: not audible tones, but meter deflections, converted by hand into short and long marks. Three shorts, three shorts, three shorts, gap, then a run of seventeen longs, then three shorts again. "That burst at 0358, the amplified one, wasn't a burst at all. It was this." He wrote it out: a long run of dashes, a short, two mediums, a short—a pattern that read as nothing in standard Morse but was unmistakably deliberate. "Two different lengths of pulse. That's information. That's code." "Code for what?" "I don't know yet. But it breaks the pattern." Omar set the pencil down. "A machine under the water, keying itself on the tide, sending a repeating distress call and then one encoded burst every few hours, from a rock we blasted flat forty years ago. There is nothing down there, Juna. There never was. I've seen the survey logs." "Then somebody put something down there." "Somebody did. And either the somebodies are still alive down there—impossible—or the somebodies built it to talk after they were gone." They looked at each other across the paint crate. The sea wind worked the tarps at the doorway, slapping and slapping, and the radio sat between them with its one hundred bars of battery life and its endless hiss. "There's one way to find out," Juna said. "What, dive Signal Rock?" "I'm a rescue swimmer. I dive. The rock is under the waterline at low tide, but at slack high tide this afternoon the water over it will be at its deepest." She picked up the page with the tide window and studied it. "If I swim out at slack, the current will be near null, and I can work the rock for an hour before the ebb starts pulling." "You have no dive gear. No tank, no regulator." "I don't need a tank for forty feet. I can freedive that. And the harbor department shed has a pair of harbor diver's boots, a lead belt, and a mask with a cracked lens—I saw them in the back when we took the tarps." Omar was quiet for a long moment. Then he said, "You're going to dive a submerged sea stack, at the edge of a forty-fathom trench, in a drowned coastal town, to find a machine that sends SOS in the dark." "I'm going to look at it. If it's a machine, we get answers. If it's a navigation buoy on the spar, we get a place to mount our antenna." Juna stood. "Either way it's the only thing in this water that's talking. I want to know what it wants." "Take the radio," Omar said. "The handheld. If you find something, key it three times and I'll know you're coming back." "Three beats. Like your signal." "Like my signal. Maybe whoever built the thing on the rock thinks the same way we do: three of anything means come home." She took the handheld, clipped it to her belt, and walked out onto the granite ledge. The olive-brown flood stretched away under the gray sky, dotted with the high corners of drowning roofs. Over on the far side of the harbor, the old buoy marker that marked the channel entrance—Signal Rock's successor—listed on its anchor chain, half-tilted, its paint pealing. The water over the blasted sea stack was invisible from where she stood. But somewhere beneath that flat, sullen surface, a machine was keeping time. A machine that knew how to say SOS. And knew how to say more.