A nearby sign stated that the building had been constructed as a locktender’s house in 1829, then enlarged twice in the ensuing years as it evolved into Great Falls Tavern. For 19th century Washingtonians who took overnight pleasure cruises up the canal from Georgetown, it served as a destination, a tavern, and an inn. But then as now, its proximity to the Falls was the main attraction.

Vin noticed that the path from the parking lot to the Visitor Center was decorated with carved pumpkins and paper-bag lanterns. Cardboard signs pointed arrows toward a goldmine and a mock gallows. A hanging banner over the gallows read “Life and Death on the Canal.”

“Must be for some kind of Halloween event,” Nicky said.

Vin nodded. “I wonder who they’re hanging tonight.”

When they reached the Falls trailhead, they locked their bikes in the rack and walked onto a cement arch that crossed a spur of the Potomac. The water in this tendon of river was white and flying and Vin was startled by its power and speed. The arch led to a wooden boardwalk that zigzagged across Olmsted Island, which a nearby sign explained was a rare example of a bedrock terrace forest. Vin noticed that the trees were all shorter and thinner than those along the canal, and that the leaves, moss, and pine needles that formed the ground-cover lay on a foundation of roots and rock, rather than topsoil. The sign claimed that trees and vegetation on Olmsted Island were periodically carried away by massive floods on the Potomac.

“It does look like this island has a different ecosystem,” Nicky said. “Everything looks miniaturized… almost fragile.”

“Like a bonsai version of the plants and trees up the hill,” Vin agreed. The walkway wove around rocks and depressions before crossing a rocky, fissured gully studded with pools of stagnant water. The roaring they had heard in the background for the last few minutes grew louder. Around a short ridge and past a swampy basin they reached the observation deck, which was mounted fifty feet above enormous rocks at the base of the cliff. They found an opening between sightseers at the railing and felt the cool breeze that drifted up to the platform from the river below. Vin’s eyes were drawn to the cycling clouds of spray where water pierced water at the base of the Falls. For a few seconds he felt hypnotized, unable to focus elsewhere.

“Unbelievable,” Nicky said, raising her voice against the roaring. “This is ten times bigger than I expected.”

Vin blinked his hypnosis away. “Even though you’d seen the photo of the Falls?”

“The scale must be hard to capture in a single shot. And the motion.”

Vin nodded. What the 1924 photo of Lee Fisher and K. Elgin at Great Falls couldn’t convey was the animation of water following every possible path downstream. At the head of Olmsted Island, the river was a half-mile wide as it slipped around and over a field of large rocks. As the island emerged on the Maryland side, a dented and fissured phalanx of rock pushed into the river from the Virginia side, framing the top of the Falls. Great Falls itself was a flowing staircase of three arch-shaped drops, each over twenty feet high and split and twisted by immense knuckles of fractured rock worn smooth like putty. Between the upper, middle and lower drops, the river crawled downstream through staggered boulders as a fabric of waves and haystacks, with thousands of white veins writhing and twisting across its sliding body of jade. The split currents converged again at the base of the Falls, pulsing downstream as a train of standing white-maned waves.

Vin looked across the river at the crowded observation decks atop the cliffs on the Virginia side. “We’re both looking at the same thing,” he said, “but what we’re seeing is entirely different.”

Retracing their path along the boardwalk, Vin studied the landscape of rocks, scrub pines and scrawny hardwoods. What generation of this island’s trees was he seeing now? The hundredth? Thousandth? Millionth? He tried to visualize the scope and power of a flood that could – that had, that would again – wash all this away. Like the people who had walked here, he thought, and fished and hunted above and below the Falls across a hundred generations, and left no trace except a handful of petroglyphs hidden in the rocks along the river. They must have left their bones here, too, interred in the underwater caverns and sieves that lace the Falls. He pictured the degraded bones of those who disappeared in the cataracts a thousand years ago embracing the swollen flesh of a recent arrival, a wader who had slipped into the river above Great Falls this summer and was never seen again.

From the corner of his eye, he saw a flash of motion in the woods upstream from the walkway. He stopped to track it, hands on the railing as Nicky walked on. Too large for a squirrel or a small mammal, but very quiet. Could it have been a deer? Was the island big enough for deer? Peering at the scrawny trees and moss-stained rocks, he couldn’t see anything moving. Whatever he’d seen was out of sight now, eclipsed by a rock or hidden in a depression. He turned back to the boardwalk and saw Nicky swing along its next leg, ten paces ahead, hands stuffed into her pockets, shoulders relaxed and low. Her short brown hair bounced and gleamed in sunlight, and her legs swung a slender arc as her biking shoes struck the planks underfoot. Animal grace, he thought, following her now, closing toward her through a mist of alienation. He didn’t really know Nicky; they were both just animals hunting. For what, he wasn’t sure.

She slowed to look back as he approached. “You OK?”

He nodded. Nicky’s eyes were warm and inquiring and he remembered visiting her during her residency at Tufts and watching her reassure an elderly man that his cat should recover completely from an eye infection. The man had said nothing, just exhaled in relief, but Vin saw his eyes water and the tension in his gnarled hand relax as Nicky spoke. Vin caught her hand with his own and they fell in step together. “I thought I saw something.”

***

As the path reached the top of the hillside and emerged from the trees, Kelsey paused to assess the backyard of the house in front of her. Seeing no humans or canines, she stepped forward onto the lawn. She was pretty sure the dog was home somewhere, and she reached into her jacket pocket for reassurance that the rawhide bone she’d brought was still there. She found it underneath her camera and pulled it out. With luck, she thought, the dog will be out on the deck like he was last weekend.

She’d only seen it from the front and the foyer, but the split-level house looked familiar. The second-story deck ran almost the length of the house and was connected by glass doors to a living room. Another set of glass doors below the deck opened into the first floor. She walked toward these doors. When her boots crunched the gravel under the deck, she heard a bump overhead, followed by a clattering of toenails and a rolling chorus of barks. She backed onto the lawn as Randy lunged to the railing and continued his guttural assault.

“Hey, buddy,” she said. “You’re a good watchdog. How about a reward?” She lobbed the bone up to the deck and it landed with a rattle that drew the dog’s attention. She proceeded to the sliding door and pulled the handle; it slid open. Cyclists are so predictable, she thought.

Her eyes adjusted to the unlit room. A mobile of smooth sticks hung from the ceiling in front of her. To the right, she opened and closed a door to an unfinished storage and laundry area. A door to her left opened into a dark garage. Along the wall near the stairs was a slab desk propped on sawhorses. The desk was anchored by a monitor and keyboard, and a skewed arc of printed pages and programming books radiated out from its center. She glanced at the books and leafed through the papers, finding nothing of interest, then continued toward the stairs.