The path dwindled drastically as the road crossed over an inlet of the Tidal Basin. Rob led the way along the foot-wide sidewalk, separated by an ordinary steel highway barrier from the clogged tourist traffic idling along beside his right hip. Under his left hand the ugly W.P.A.-era bridge rail was made of concrete uprights and clunky rectangular ironwork painted green. Edwin followed at his heels, still simmering with questions. "And suppose we walked over to the White House? Would there be a President there? Who would he be? George Bush, or that other guy who ran against him, I forget his name, Clinton?"

Suddenly the water beside Rob burbled and boiled. A deep and gluey voice roared, "Who's that tripping over my bridge?"

Rob halted, completely unalarmed. He recognized that voice. It was his own, the ominous troll-voice he had perfected for Angela and Davey. In his opinion this overpass barely merited the honor. "Ed," he said. "Does this even rate as a real bridge?"

"There's water on both sides," Edwin pointed out, gulping. "Rob, who was that?"

Rob smiled. "It's the troll, Ed-did you ever read the fairy tale? He lives under the bridge."

Big oily bubbles rose to the surface, bringing up a smell of swamp and decay. "Who's that tripping over my bridge?" the troll yelled again in earthquake tones.

"This is uncanny," Edwin said.

"That's what this place is like," Rob agreed. "Scary, but fun too." Serene, he leaned over the iron rail. In the shadow of the low bridge the water was gloomy gray. There was no gap between the bottom of the overpass and the sullen surface of the water. "I'm Rob Lewis," he called down.

"Then I'll eat you up!"

"You don't want to eat me," Rob said. He had nearly said "meeee," in billy-goat bleats! "There's another guy coming just behind me, with a lot more meat on him."

He grinned back at Edwin, who waved his hands in negative denying motions and pulled a comic horrified face. "Leave me out of it, why don't you?"

Edwin whispered. "Why doesn't the troll yell at all these cars?"

"He doesn't know there are people inside? He doesn't want to become a traffic fatality? Don't sweat it, Ed-just refer the troll to someone even bigger and tastier following us. That's how it worked in the story."

The water blurped and bubbled disgustingly again. "No," the troll bellowed.

"I want-you!"

Something shot with a tremendous spurt of icy water straight up at Rob, a greenish slimy paw at the end of an impossibly long boneless arm. With horrible sticky strength, it clutched Rob's chest and throat. He gasped, thrashing in terror as the thing dragged him down. He tore at the cold strangling grip with desperate hands.

"Holy Mike! This is impossible!" Edwin stared around wildly, searching perhaps for a policeman.

"Ed-help me!" Rob choked. "It's pulling me over-"

Just in time Edwin locked his powerful hairy arms around Rob's waist.

"Don't worry, bud," Edwin panted. "I've got my legs hooked around a concrete baluster. We're rooted like Gibraltar. Holy Jesus, why isn't anybody getting out of their car?"

But the vehicles crept by without pause. It was as if underwater monsters plucked pedestrians off this bridge every day. Fire swam in his eyes as Rob forced first two fingers, and then three, between his throat and the stinking green death-clutch. He was stronger than this monster. He had defeated Gilgamesh and stripped him of everything. This troll wasn't going to get him. He dragged the paw relentlessly off his neck.

As if it sensed defeat, the watcher in the water abruptly switched tactics.

The oozy grip turned itself inside out with rubbery ease and fastened with numbing strength on Rob's wrist. "No!" he gasped. But the swift outward jerk on his arm nearly dislocated his shoulder, and plucked him neatly right out of Edwin's grasp.

"Rob!" Edwin yelled, lunging.

With a splash, Rob was reeled under. The water bit icicle cold through his khakis and sports shirt. Here at the edge, the Tidal Basin couldn't possibly be more than a couple of feet deep. Yet the implacable arm sucked him down and down with fearful speed into the gelid sunless water. He could see nothing, and a roaring noise filled his ears. I'm going to drown, he thought in terror. I didn't breathe properly before I went under. I'll black out and then drown. He struggled feebly, hopelessly, and felt something dragging on his right foot. Something warm, clinging to the ankle-Edwin!

The knowledge calmed Rob's panic a little. This is my place, my country, he told himself. I can't drown here. Nothing can hurt me. Still he didn't quite dare to open his mouth and inhale the water just yet. He could hold out another few seconds-

With a rush and a buffet Rob's head broke the surface. He had arrived. The grip on his wrist was gone, and the darkness was absolute. Gasping, he groped forward and touched a slick rough surface. It was a narrow place, a ledge perhaps. Wheezing for breath, he levered himself onto it. He was deep under the foundations of the bridge, in a tiny underwater nook that had trapped a bubble of air.

Edwin fumbled at his leg, and Rob reached in the dark to help him up. The sound of their rasping breath echoed close around their ears. The place must be very small.

When he recovered a little, Rob wiped away the water streaming from his beard and hair. "Told you so," he panted. "Dangerous."

"Right. Rub it in." Water splashed and dripped in the dark as Edwin shifted to sit on the narrow slope beside Rob. "What do we do now?"

"I don't know." In this country he could speak the truth without self-consciousness. Rob leaned back against what felt like a stone wall. He knew what was coming, very soon. "Ed, I-I'm terrified."

"Very sensible," Edwin panted. "I'm scared spitless myself. Lost my notebook, too. But if I still have my Swiss Army knife ..."

It was so dark Rob could distinguish no difference if he opened his eyes or shut them. He glared out into the void anyway, stubbornly hoping to glimpse his enemy. How could he have ever dreamed the monster had fled? Fear jerked and plucked at his nerves, grinding in his stomach like gravel. "We're not really trapped here, Ed," he said, steadying his voice with an effort.

"Takoma Park, the bench by the pond- we can get back in a second. Then he can't get us. I'm in control. I can push the 'abort' button any time."

"Let's think about that," Edwin said. "Is this troll here the monster you were talking about?"

Rob nodded, but then remembered Edwin couldn't see him. "Yeah," he said huskily. "Up there on the bridge. He knew my name."

"Then he's the gent we've come to see. There's no point in running away from him-you did that before, am I right? Let's try to see it through this time."

Rob hitched himself up onto the slippery ledge again. It was true that nothing horrible was happening right this moment. At any time he could pull out. Nothing could hurt him here. He swallowed the lump of irrational fear in his throat and said, "You want to just sit here in the dark for a while, before we go?"

Close beside him, Edwin gave a grunt of satisfaction. "It's a shame I'll never be able to tell anyone how clever I am." And a tiny spark of light came to life in Edwin's hand, pushing back the dark.

Rob goggled at it. "Ed-how?"

"Halogen button light," Edwin said, grinning with justifiable pride. "I buy them at the camping store, mainly for the Mazda-so I can unlock the door at night without scratching the finish. I keep it on the ring with my knife.

It's only powered by a couple watch batteries, though. So it won't last us long. Here-since the troll is after you, you take this."

He passed over the Swiss Army knife. It was the little one, not the massive four-inch Gerber multi-purpose tool Edwin kept for camping trips. Rob snapped open the biggest blade. He had seen Edwin use this to slit open cookie packets and cut the tape on parcels. It was less than two inches long, totally comic as a defense. Rob gave a laugh so weak it sounded like he was choking. "Ed, this thing wouldn't stop a mouse."

"It's wonderful what a little light will do," Edwin said, replying to the tone rather than the words. "Let's boogie, huh? Come out, troll," he called softly, lifting the light. "Come where we can see you."

The tiny glow just barely illuminated a rough concrete ceiling. It was very low, too low to stand under, and came down to the black water all around.

Their slimy ledge, the only footing, was about three yards long. Rob held his breath and listened. The only sound was the drip from their sodden clothes.

After a long moment Edwin said, "You want to give it a try?"

"No," Rob admitted. "But I will." He raised his voice. "Where are you? Come out!"

The space was too small for a creature of any size to hide Rob stared at the ominous black surface of the water wondering if trolls were amphibious.

Edwin shifted to a crouch his tennis shoes squelching. As the light moved with his motion Rob caught a glimpse of something out of the corner of his eye. In the dark, beside him in the shadow-"No!" he yelled, throwing himself back.

Edwin grabbed Rob by the shoulder before he plummeted into the water again.

"It's okay, Rob!" he said. "I-I know you."

Edwin was staring past him at the troll. Rob looked too, and gulped. It was not really a movie monster with slimy tentacles. Or the green spiny troll from the twins' favorite book, or even a Mesopotamian monarch. The third person in this tiny space looked like a drowned man. His face was greeny-white, and weeds clogged his long pale hair and beard. Water streamed from his colorless rags, and he glared at them out of deep-set icy gray-blue eyes-the eyes of a wolf.

"I know you," Edwin repeated, kneeling up. He ducked his head under the low ceiling, watching the drowned man intently across Rob's sprawled body. "You did a Heimlich on Katie. You stood up to the casino doormen. You fought to save my life. You are not a bad person. You are Rob Lewis too."