He stopped, listened. The same steady note. It came from below, downshaft, toward Central.

Then his ears popped.

He reeled in his tools and pushed off, all in one smooth uncoiling motion. A burst from his jets and he plunged inward. Phosphors dotted the shaft with pools of yellow-green light every hundred meters; automatically he used them to judge his speed, to keep from picking up momentum he wouldn’t be able to brake. Smears of green gunk covered some of the phosphors, growing on the wan energy they put out.

He passed tunnels that ran horizontal, 3B, 3C, and 3D, but the sound wasn’t coming from them. Coming toward 3E, he slowed because the whistling was getting louder and a steady suction was trying to draw him downward. Carl had always hated high-pitched noise and this was now shrill, grating. He was searching for a split seam in the insulation but wasn’t at all ready for what he found.

Worms! He blinked, stunned.

Purple snake-like things oozing, wriggling. Moist, slick, waving slowly, ringing 3E’s entrance. It was like a living mouth calling with a cutting siren wail, the wind moaning and tugging and sucking him toward the beckoning purple cilia that eagerly flexed and yearned and stretched out toward him—

He fumbled at his jets and pulsed them hard, backward. Wind swirled by him, sending his tool lines streaming away, tearing the wool cap from his head, ruffling his hair. He twisted and caught a handhold in the shaft wall. The noise was deafening now and he knew he was getting rattled by it.

What the hell—!

He ripped open his emergency pocket and fished out a plastisheet helmet. It took a long moment to tuck it into the O-ring seal in his skinsuit. I haven’t practiced this drill in a long time.

It caught. He pulled the FLOOD bottle tab. The bubble expanded with a reassuring whoosh of air. That provided some sound insulation, but not much. Not enough.

“It’s at Shaft Three, Tunnel E,” he sent over the emergency channel. “Three E, Three E, Three E. Bad. Whole area around the collar is ruptured.”

A faint voice called in his bonephone, —… can patch with spray foam? Got some on its way.

“I doubt it. Something… something’s broken through. This sure isn’t just a rip.”

Carl bit his lip. He didn’t know how to describe it. The team would take only a few minutes to get here, but the shaft was losing torrents of air.

The purple…things…must’ve broken through to a crevice leading up to the surface.

He launched himself across the shaft. The wind blew him several meters before he hit the far side and managed to hook a temporary clip into the insulation. He hung on and watched the nearest of the purple worms twist and pulsate, rivulets of ocher sweat running down from the pointed tip. The wind blew the drops away, sucking them back into the gaping hole that ringed the base of the worm.

The horrible thing bloated, contracted, bloated again—each time prying the insulation wider, admitting more of it into the shaft. The nearest was at least a meter long and visibly growing, convulsing in a slow agony of swell and clench, swell and clench. Its maw glittered with what looked like crystals of native iron.

They’re after the green gunk, he realized as the worms pressed against the layers of mosslike growth within their reach. They seemed to absorb it directly. They’re grazing on the stuff!. And sucking threads out of the air.

Around the aluminum and steel collar of 3E’s entrance Carl counted thirteen of them. He played out some line and the howling gale sucked him down, toward one of the eyeless, slime-sweating things.

Carl clenched his teeth. He was breathing bottled air now but he’d swear he could smell it—cloying, thick, humid, like ripe, moldering leaves.

He unhooked his laser cutter, thumbed it to max, and fired at one. The beam drove a thin red line straight through it… with no significant effect.

He made the next bolt last longer and sliced the thing off a few centimeters above the base. A spray of purple-red whipped away into the wind. The top wobbled and fell aside, then tumbled slowly away.

More fluid seeped from the wound and then it began to film over. As Carl watched the thing began growing a thickening crust. The new matter had a rich, glossy purple skin like an eggplant. Then it began to thrust outward, sideways, outward again—onward, into the shaft, the wound only a momentary interruption.

Carl felt the hair rise in prickly fear along the back of his neck.

—… it like now? Repeat, can’t pick you up, want to know…—

The rest was lost. Carl could see no one in the shaft. Where were they?

He pulled his patch gun from its holster on his left calf. It was intended for small work, but he couldn’t think of anything else to do.

To get closer he played out another meter of line, then hastily drew some back in as the burgeoning thing waved his way. Could it sense him? Without eyes or any visible organs? Maybe his body heat. He wasn’t going to take any chances.

The patch gun spat a wad of yellow gum at the hole. It splattered over the opening, spreading quickly as the long chain molecules grasped for the maximum surface area to bond. The suction bowed it inward but the yellow patch held.

For almost a minute. Then the worm butted against the cloying yellow film, wrenched, flexed—and shook it free. The wind tore at the loose edge. It flapped futilely like a ragged flag.

“We’ll need the big stuff,” Carl sent. “Bring all we got.”

—… can’t hear… any other measures… take to be sure…—

“Yeah. Seal all locks. Everywhere.”

—… don’t under… we’re sending all…—

“If we run out of sealant, the locks are our only backup.”

And if that fails, he thought, we’ll have to live in suits.

Ten minutes later, that didn’t seem so unlikely.

Only Lani and Samuelson and Conti were available to help right away; crew was stretched thinly everywhere. Lani was a spacer, quick and smart, but the other two had been pressed into jobs they didn’t know.

They worked as fast as possible. Chopping the tendrils was simple, but more pushed in before the sealant could harden. Carl and Samuelson discovered that to make any progress at all, they had to get close into the tip in the insulation and clear out the whole area, cutting all the way back to the ice.

—Got to slice it clean away,—Samuelson said. The large man licked his lips nervously. —Damnedest stuff I ever saw.—

“Watch out there with that torch, you’re close to the ice.” Carl had to hold Samuelson on a rope to keep the man from being sucked directly against the hole. The team had rigged a set of linchpin stays and lines to keep the howling wind from plucking them off the shaft walls. Now the shrill, hollow shriek slowly dulled as the air in Shaft 3 finally ran out.

Carl shouted. “Don’t get to close!”

Too late. Samuelson’s big industrial laser had finished off the purple stuff, all right—and then hit a vein of carbon-dioxide ice, vaporizing it instantly. A gout of steam shot out of the hole and blew Samuelson away, spinning.

“Lani! Slap that sealant in now,” Carl sent. He released the line, letting Samuelson get clear. It was going to be messy around there in just a second.

Lani maneuvered at the end of a tether, holding the snaking blowline in both hands. —Here goes.—

Sticky yellow sealant spattered over the cleaned holes. Carl and Conti played fan lasers on it at the lowest setting, to flash-dry it.

Lani worked her way around the collar of 3E, shooting thick coats of yellow over the rents. Here and there it buckled from pressure, but she quickly spewed more on to reinforce the barrier.

—Not supposed to use it this way,—Conti sent. —Too thick. We’ll run out.—

Samuelson returned, velcro-climbing the walls to rejoin them. —Anything thinner, she’ll crack right through.—