"We're getting there," panted Napoleon, "come on."

The clashing of weapons came from behind and all around them in the hundreds of side tunnels. Wendles slept all over the vast sewer complex and could be out of bed and dressed for an emergency faster than a crew of London firemen.

"If we don't get to the river first," said Napoleon, "we'll be up to our necks in mud before the night's out."

They redoubled their efforts and, though their lungs were bursting, they ran faster. Now Chalotte and Orococco took the box, not even breaking their stride as they snatched up the burden.

At last, with a cry of relief, they burst out onto the underground bank of the river, as dark green as ever, the tenacious mud bubbling just below the surface of the water. The tow-path was wide at this point and there rode their boat, The Silver Belle Flower , tied to the bank. Napoleon drew his knife and slashed the painter.

"In with the box. Stonks, round to the front, you've got to pull real fast till it's wide and deep enough to row; then we've got to go like Oxford and Cambridge gone bonkers."

He glanced up the tunnel. The noise of pursuit was getting nearer; any minute now they would be overtaken. Napoleon took Knocker by the arm.

"Knocker," he whispered urgently, not wasting a word, "see that tunnel just behind us? It goes straight to the Thames; the river meanders. If we all get in the boat the Wendles will run straight down that tunnel and be at the outlet before us, cut us off and do for us. Two of us have got to stay here and stop them getting into that tunnel, give the others ten minutes', quarter-of-an-hour's grace, then they'll get away. Otherwise they won't. You and me?"

Knocker looked behind him and back up the tunnel from which the pursuers would issue. "Not you," he said. "You are the navigator, you know the Wandle and you know the Thames. I will stay."

"Not alone," Torreycanyon said, and pushed in between them. "Knocker is right; you must go. Two of us will be enough. Straight down that tunnel, you say? When we have dealt with the Wendles, we will catch you up."

"Wait a quarter-of-an-hour," said Napoleon, "but be careful when you go down the tunnel, there's a guardroom down there, too. I'd better stay, all the same, three is better than two."

"Then I will stay," said Orococco, who had leapt back out of the boat to see what they were doing. "Just make sure that Tooting's share of the money gets to Tooting."

Napoleon took off his bandoliers and gave them to Knocker, and the others in the boat, when they realised what was happening, each removed one of their bandoliers and threw it to the bank. Then they stood sadly, just looking at their three comrades.

"Oh, go on, Stonks, go on, run," shouted Knocker, and the boat jolted away and Napoleon leapt aboard as it left the shore. Knocker watched the boat spurt out of sight round the first bend, pulled steadily by the never-tiring Stonks. There had been no time for farewells and no time for pity.

"We'll never see them again," said Knocker.

"Well, we still got each other," said Orococco and he picked up the bandoliers.

"Let us go out with a fight," cried Torreycanyon excitedly.

"Yes," said Knocker, "whatever happens we've won and Flinthead and his pointed skull and his petrified grin will not laugh like we will laugh tonight."

"We'd better get into the mouth of the short-cut," said Orococco. "We can't possibly hold them here."

They crossed the Wandle, up to their waists in the foul slime of the riverbed, and adopted defensive positions. As they took cover, an advance party of Wendles came careering out of the main corridor and a shower of well-directed high-velocity stones rattled around the Borribles' hiding-place.

"Man," said Orococco, "I'll go white with the shock."

"This is no time . . ." began Knocker, and then stopped and laughed instead, and they knelt in the gloom and laid their bandoliers and lances beside them.

Within a few seconds the open area by the landing stage had become crowded with Wendle warriors and Tron appeared in the midst of them, his face flushed with anger.

He instantly ordered a large detachment of his men to follow the course of the Wandle in pursuit of the boat. Into the branch tunnels he dispatched smaller patrols to make sure that the fugitives were not lurking there, but the main body of his troops he directed into the short-cut so that he could block the mouth of the Wandle with a considerable force before The Silver Belle Flower could ever get there.

"They can't get away," he shouted. "We'll have them yet, suffocating in Wandle mud."

"Let us hold our fire till they get halfway across," whispered Knocker, "and we'll soon see who is in the mud first."

Already the Wendles, ardent and fanatical, had plunged into the filthy water and were wading across. Tron himself was carried shoulder high by two of his personal guard.

The three Adventurers loaded their catapults in the darkness and they waited until Knocker hissed, "All right, now!"

Three well-aimed stones each struck their targets and three Wendles disappeared under the mud. The Adventurers fired again and again and the rate of their fire was phenomenal, but the Wendles came on in spite of their losses, for they did not lack bravery.

"Aim for Tron," cried Orococco, "or his guards."

Knocker shifted his aim to one of Tron's porters, and his stone struck the bodyguard solidly on his helmet and he lost his footing on the river bottom and Tron was pitched face foremost into the Wandle.

"Swallow that! " said Knocker with relish.

Tron was pulled to the bank by his followers and the mud was wiped from him. This victory gave the three defenders a short breathing space but Tron was not a Wendle to allow his enemy to relax for long. Wave after wave of warriors he sent into the river, and although the Adventurers fired till their arms were aching, they could not stop the warriors crossing in force and spreading out to right and left of their tunnel.

When satisfied with his bridgehead Tron ordered his Wendles to attack. Fortunately only three warriors at a time could enter the short-cut and deadly work was done with knife and lance in the darkness, as Torreycanyon and Knocker and Orococco fought side by side for their lives and the lives of their companions.

Suddenly Tron's voice was heard calling on his soldiers to cease fighting for a moment and the attackers fell back. The three Borribles leant against the wall at the tunnel entrance, exhausted and nearly done for.

"How long has it been now?" asked Knocker. "My watch is smashed."

"Quarter-of-an-hour," said Orococco triumphantly. "We've done it."

Tron called again. "You Borribles in there, you might as well come out, you're surrounded. The boat has been captured, we've got the box again. You are fighting for nothing, I tell you. Save your lives."

"Don't believe him," said Knocker. "It must be a trick, they've got clean away."

"Keep them talking, anyway," said Orococco, "it's not so dangerous as fighting."

"Show us the box," shouted Knocker hoarsely, "then we might believe you, Tron."

Tron laughed. "Your friends will be here soon, in chains, then you will see the box. Surrender, cause no more trouble and we might be lenient with you. You have fought well, that is enough."

"We would rather fight here than go back to your dungeons," shouted Knocker.

"There'll be no dungeons for you, friend," called Tron, his voice hardening.

"I can believe that all right," said Orococco quietly.

At that moment a runner bounded up and spoke to Tron. The crowd of warriors fell back and the onlookers saw Flinthead himself arrive, surrounded by his guard. His face was stern and cruel and he was dressed for war.

Flinthead took in the situation at a glance. He gave orders and his guards looked at the roof of the cavern where they stood, then they ran forward and climbed one upon the shoulders of another until the last man reached the ceiling and disappeared. A rope-ladder was thrown down to the ground and half a hundred Warriors scrambled up it and went out of sight.

"What does that mean?" asked Knocker.

"It means trouble," said a voice behind him and the Adventurers spun round, weapons at the ready.

There stood Napoleon Boot, covered in mud and gashed in the head, his helmet gone and his jacket torn.

"What's happened?" cried Knocker aghast.

"It's all right," said Napoleon breathing heavily. "They got away, I saw to it. They'll be out on the Thames by now, I shouldn't wonder."

He sank to the floor and leant his back against the wall.

"How did you get back here, man?" asked Orococco, kneeling beside the Wendle and inspecting his head wound. "My, that sure is a beauty!"

"When the boat was safely away," explained Napoleon, "I made for the short-cut. The guard had been alerted but they didn't know I was part of the getaway. As we were talking, some Warriors appeared along the Wandle and shouted to the guard to hold me. I had to fight my way out. They can't be far behind; not a lot of them, but enough."

"What's Flinthead playing at?" asked Knocker.

"He's sending Warriors up to the surface. They'll come down through a manhole behind us. When he's got us surrounded, he'll come and talk to us, or just starve us out. He can wait. He can't know yet that the boat is clean away."

"Well, it's nice to hear such things," said Orococco, "but why risk your life to come back to tell us?"

Napoleon hesitated and then went on. "I haven't told you all the story, yet. There is bad news. Halfway down to the mouth of the Wandle we were jumped by a large night patrol coming back from outside. They saw the box, and guessed something was up and didn't wait to ask questions. Stonks went under the water with five of them on him, but he came back up again—alone. There was about twenty of them around the boat. They dragged the box out and we dragged it back in. We fought like double our number. Honest, Knocker, we fought like tigers."

"They got the box," said Knocker, in anguish.

"No, they didn't," said Napoleon, emphatically. I'd have died, rather . . . after everything."