When he managed to control himself-boy! had he needed a laugh-Mark pointed at his muddy coveralls. "Look," he said, "this is the best I could do following Yerby step by step."

The Zeniths already appeared cowed and puzzled. Mark grinned and continued, "If you think you can torture directions out of him, you'd better think again. He's got to lead, and he's got to be free when he does. I couldn't find my way back across the patch right there, and I just came over it."

He swept his hand in a broad circle at the rippled muck behind him.

"I can't let you keep your guns, you see," Yerby said in a tone of calm reasonableness. "But they wouldn't do nothing save drag you under if I did. You'll have work enough getting back to dry ground as it is."

Biber scowled. Instead of answering immediately, he walked a few steps in the direction from which Mark and Yerby had arrived. Maybe he was looking for footprints.

"Watch," Yerby said to Captain van den Brook. He put the tip of his thin rod on the ground beside him and thrust it several feet down at an angle.

Biber turned to see what the frontiersman was doing. A huge bubble, nauseating with sulfur and rotting vegetation, burped from the gooey soil at Biber's feet and swallowed him.

"Eee!" the Mayor screamed as he sank.

Yerby stepped over, grabbed, and dragged Biber up by the collar just as the return wave was about to flow over the mayor's mouth and nose. Yerby smiled at the man he held. "D'ye take my point, son?" he asked gently.

"Stack arms!" Captain van den Brook ordered. Biber nodded, but he was still too terrified to speak.

"Not there, boy!" Mark shouted at a Zenith policeman probably twice his age. "Bring your foot another six inches left or you'll sink to the other side of the planet. And I'm hanged if I bother to fish another of you losers out!"

Triumph had brought out a facet of Mark's personality he was pretty sure he was going to be ashamed of in the morning. Furthermore, the feeling of power didn't bring any real strength back into his muscles. His arms seemed to weigh tons, not just from the coating of mud he'd gotten pulling Zeniths to safety, and his legs were numb.

But oh! the triumph! Yerby led the column. He'd left Mark at the first really tricky spot, a dogleg where the bush that looked like a perfect handhold was actually covered by hair-fine poisonous thorns. When Mark had chivvied the last of the prisoners past that point, he'd tramped his way to the front of the line again.

Yerby had used him three more times as a human signpost. That made Mark as proud as the praise Dr. Kelsing had given his seminar paper, "The Evolution of Civil Law on Quelhagen."

After the first hundred yards of The Goo, a couple dirigibles had moved close to the line of march. By then, any weapons the Zeniths might have concealed in their clothes were too gummy to be used to hijack a vehicle. Ropes dangling from the dirigibles pulled a number of floundering Zeniths from the muck, but none of them were allowed to ride. Yerby was making sure that the invaders were punished and humiliated as well as being defeated.

In one sense that meant a lot of unnecessary effort for him and Mark, but Mark knew that it was at least as important to prevent the Zeniths from repeating their invasion as it was to stop them dead this time. He didn't think any members of this police unit would be back to Greenwood during their present lifetimes.

"Come on!" Mark snarled to the back of the last Zenith, who was swaying on the trunk of a sapling to gather strength. The hands of the folk ahead in the column had worn away the tree's soft bark. "You'll have plenty of time to rest when you head back to Zenith in a freighter's hold. Move it!"

Mark's civilized part was amazed at the way he was acting toward the prisoners. You'd have thought he was a frontiersman as barbaric as Yerby himself. The Zeniths probably did think that…

A dirigible dropped close. Amy wasn't in this one, but she'd followed most of the line of march with her camera. A dozen dirigibles bobbed through the foliage in the near distance. The lip of the basin had to be close.

Mark's boots scraped the first firm ground in what felt like a lifetime. The vegetation changed abruptly from fleshy shrubs to Greenwood 's equivalent of grass. He was out of The Goo.

"There you are, lad!" Yerby boomed. He offered a hand-blown bottle. "Say, I'll tell the world that you're a man! Come have a sip of something to cut the mud, why don't you?"

Well over a hundred Greenwood settlers, armed to the teeth, guarded the Zeniths on the downslope beyond The Goo. Many of the Greenwoods carried weapons that the police themselves had left behind at the Aten.

Groups of ten or a dozen prisoners at a time were herded into cargo nets slung from dirigible gondolas. Amy had her camera out. The Zeniths would squeeze together like fruit in a mesh bag when the dirigibles rose, but Mark didn't suppose anybody'd be seriously injured in the short flight to the Spiker.

He managed to stay upright for the few steps it took to reach Yerby and the bottle. Other Woodsrunners stood nearby, nodding to Mark with obvious respect. Yerby sounded as vibrant as he ever had, but Mark noticed that the big man was leaning on his staff. He'd dragged Zeniths from the clinging muck dozens of times during the trek; exertion like that took a toll even on Yerby.

Mark lifted the bottle, knowing that everybody was watching him, and drank deep. He gagged, coughed, and spewed the liquor out through his nostrils. It burned like molten lead on the delicate mucous membranes.

"Atta boy!" Yerby said, pounding Mark's back. "Clean the goo out, and by all that's holy, that's just what he did!"

The frontiersman expertly retrieved the bottle from Mark's numb fingers and went on, "Now, let's get off to the Spiker and finish this game, shall we?"

"Sounds good to me," Mark wheezed.

Yerby had to walk him onto the deck of the Bannock dirigible. It was nearly a minute before Mark's eyes stopped watering enough that he could see again. If what was in the bottle was whiskey, then Mark would ask for varnish remover the next time.

Desiree was at the controls. They were the last of the line of dirigibles, none of them more than twenty feet off the ground because of the overload of prisoners dangling below in the nets. Zeniths cursed with all the strength the trek had left them, which wasn't very much.

Flyers circled overhead like insects dancing. Mark had noticed that settlers hadn't taken them over The Goo, though. If bad luck or bad judgment landed a flyer in the slime, it and the pilot would sink out of sight before help could arrive.

The crusted mud was starting to flake off. Mark now itched as well as felt filthy.

"I can't believe I did that," he whispered. The phrase was starting to be a habit. He wondered how many more times he'd say it on Greenwood.

He wondered how much longer he'd survive on Greenwood. Assuming that he'd really survived this time. He was so tired…

Yerby took another pull from the bottle and hugged Mark with one arm. "You did fine!" he said. "Amy, child? Did you get a ship at the Spiker to take these fools off-planet soonest?"

"Yes and no," Amy said. Mark had expected at least a minor explosion to follow "Amy, child," but she looked affectionately at both men. "Captain Krause of the Brother Jacques is willing to take them to Dittersdorf, but he wants you to pay him before they board. Since most of them will have to make the flight awake, he's doubtful that they'll be in any mood to pay when they arrive."

Yerby chuckled. "I'll see he gets paid," he said. He nodded toward the cabin and said in a lower voice, "Surprised Desiree didn't tell him to load them or she'd stick him for a bow ornament on his ship."