"Armstrong!" Skeeter yelled, scrambling to his feet. The detective stirred sluggishly, but staggered up. Skeeter braced the Wardmann-Wolfe agent when Armstrong nearly fell, again, reeling and dizzy on his feet.

"Was Kaederman in that shed?" Skeeter shouted, barely able to hear his own voice.

"What?" Armstrong shouted back, voice tinny and distant through the ringing in his ears.

"Kaederman! Was he in there?"

"No! Saw him bolt for Redriff Road, right after he broke open one of those casks. Struck a match and threw a damned blazing rag right onto the loose powder, then ran out the other side!"

"Black powder? Good God!" No wonder the whole transit shed had gone up like a bomb. Unlike modern, smokeless powders, black powder was genuinely explosive, deadly as hell in that kind of mass. How many stevedores were killed in there? Skeeter wondered as he dodged and jumped across burning timbers and twisted, smoking tin shingles.

He reached the terminus of Redriff Road and searched wildly for any trace of Kaederman. He swore... Then heard shouts and curses drifting down from the direction of Greenland Dock. Any disturbance was a good bet. Skeeter raced that way and pelted slap into an angry group of Scandinavian sailors, cursing to make a Viking raider proud. A whole stack of crates had been knocked down, breaking open to strew their contents of valuable furs into the mud, white ermine and sleek mink and glorious black sable. Then Skeeter caught a glimpse of Kaederman far ahead, running down Plough Way through Commercial Yard on a direct course for Gate Eighteen.

And Kaederman's diversionary tactics abruptly backfired right into his face. He hadn't quite reached the gate when a whole squadron of irate constables burst through, inbound. London's river police, responding to the emergency. Kaederman, clutching an up-time pistol in one hand, skidded to a halt. For an instant, Skeeter thought he meant to shoot the entire police squadron. Then he doubled back, instead, and raised his gun directly at Skeeter.

Shit—!

Skeeter ate mud. He skidded face-first on his belly and tried to bring up his own pistol. There were too many innocents in his line of fire. He spat filthy muck and rolled frantically as Kaederman dodged past, firing at him on the way and shoving aside the furious sailors busy rescuing their sodden furs. Kaederman fired at Armstrong, Tanglewood, and Margo, too, as he ran toward them. The hail of bullets sent all three headlong into the mud. Then he raced along the very rim of the quay at water's edge and reached Redriff Road again before they could turn their weapons on him.

Swearing and spitting, Skeeter propelled himself to his feet, covered head to foot in slimy, foul mud that carried a rank stench into his sinuses. He didn't want to consider what might be in that mud. Armstrong was in the lead as they burst out of Commercial Yard in pursuit. Kaederman was a sizeable distance ahead, but even Tanglewood and Margo were gaining ground and Skeeter, abruptly in the rear thanks to the about-face, was steadily catching up.

Kaederman headed this time for Gate Three, the principle entrance to Surrey Commercial Docks. And once again, his delaying tactics with the black powder backfired. A horse-drawn fire engine, bells clanging madly, charged through, followed closely by four more. The fire engines completely blocked the way as they swung into the dockyards. Trapped inside the walls, Kaederman turned north toward the warehouses alongside Albion Dock. River police had taken up the hue and cry, as well, shouting at the fire officials to send word for another squadron.

"We've got us a bloody arsonist!" a policeman behind Skeeter yelled, fury lashing his voice. "Damned Fenian bomber, blew a shed of gunpowder to hell! Try and head him off at Gate Two..."

Rain slashed down across Skeeter's face in blinding gusts and unpredictable squalls. The mud under his boots sent him slipping and sliding for purchase in the choppy mess. At least it washed the reeking stuff off his face. Kaederman didn't try any delaying tactics at Albion Dock. He passed the warehouses and a gang of startled stevedores at full tilt, racing for Gate Two and escape. They charged past another huge basin in a straggling, strung-out line, then Skeeter caught up to Doug Tanglewood and Margo. They ran—as he did—with guns clutched in wet, muddy hands.

"If he gets out of this dockyard, we're sunk!" Skeeter gasped.

"Looks like we're sunk, then!" Margo spat back.

Kaederman had just slipped through Gate Two, with Armstrong hard on his heels. Skeeter put on a burst of speed and drew ahead. By the time Skeeter shot through Gate Two, a second squad of river police had put in appearance, running north from the direction of Gate Three. They were still in the distance, however, nowhere close to Kaederman. He was just visible on Rotherhithe Street, dodging past startled pedestrians on the pavements, cutting around large groups by ducking into the street. Horses flung their heads up and reared, shrilling a sharp protest at his erratic flight. Skeeter had just caught up to Armstrong when Kaederman cut sharp south again, leaving Rotherhithe Street.

"Where the hell is he going?" Skeeter gasped. "The river police are down that way!"

For a long moment, Armstrong didn't answer, too busy dodging past a protesting carthorse and its cursing driver. Then a startled expression crossed the detective's face. "Surely not?"

"What, dammit? Where's he heading?"

"The tunnel?"

It took a few seconds for Skeeter to call up his mental map of the area, memorized before leaving the station, then he had it: Isambard Kingdom Brunel's Thames Tunnel, connecting Rotherhithe and Wapping. Twelve hundred feet long, it had taken eighteen years and countless lives to build. It was also the only way to get from Rotherhithe's Surrey Docks to Wapping without detouring to London Bridge—or swimming.

"Isn't that a railway tunnel now?" Skeeter asked as they ran, heading helter-skelter straight for the tunnel's entrance.

"Yes! Trains from London to Brighton, owned by East London Railway Company. But the railway uses only one of the tunnel shafts! The other's still a pedestrian tunnel!"

"Aw, shit, you are kidding, right? If he makes it to Wapping..."

Unfortunately, Armstrong was not kidding.

He was also correct. Sid Kaederman plunged into the circular structure that housed the Rotherhithe entrance to the Thames Tunnel and vanished from view. They followed at a run, clattering past startled men and women in working-class garb. Skeeter and Armstrong pounded their way through the vast entrance, with Margo and Doug Tanglewood on their heels.

The entrance was a circular shaft at least fifty feet across. Skeeter peered past wrought-iron railings as they plunged down the broad, double-spiral stairs. The shaft was a good eighty feet deep and Kaederman was already halfway down, plunging three and five steps at a time. Skeeter's muddy boots skidded on the stone treads. Down and around, in a broad, lazy spiral, a dizzying gyre that would prove fatal if he put so much as one foot wrong. Down, down to goblin town...

He was beginning to pant for breath when they finally reached the landing where the double spiral came together. Half-a-turn more and they were on the ground, paving stones clattering underfoot. The Thames Tunnel loomed before them, a double-barreled shotgun nearly a quarter of a mile long. The air was dank, foetid, cave-like. The tunnel walls exuded a chilly sweat, moisture running in tiny rivulets like the condensate on a beverage glass. Twin tunnels receded into infinity, dimly lit at regular intervals with gas lamps. Railway tracks ran down the center of one side.

"Which tunnel?" Skeeter gasped as Tanglewood and Margo bounded down the last few steps to join them. "Which one did he go down?" They listened intently at each entrance for the echo of footfalls. The chugging of water pumps growled and echoed. They couldn't distinguish anything like a sound of running footsteps against the background noise.