Tunnels 02, Deeper

organized.
    "Can I give you a piece of advice?" she asked as he was tying the pad of stove guns back onto his thigh.
    "Sure. What?" he replied, not knowing what was coming next.
    "It's the way you move. When you tread, you're like the others -- even Drake. Try to use the ball of your foot... stay up on your toes longer, before you lower onto your heel. Watch me through the scope."
    He did as she told him, observing how she took each step, moving like a cat sneaking up on its prey. Through the scope, her pants and boots, drenched from the water of the sump, glimmered with a shifting green of pale yellow light.
    "It cuts down on the noise and even the tracks you leave, a little."
    Will watched her legs as she demonstrated, marveling at what seemed to be second nature to her.
    "And you'll need to learn about foraging," she said suddenly, noticing something on the rock wall beside her. "There's plenty of food around if you know where to look. Like this, a cave oyster."
    She went over to what he thought was merely a piece of rock jutting from the wall. With the blade of her knife, she began to pry around it. Then she resheathed the knife and put on a pair of gloves.
    "The edges are sharp," she explained, tucking her fingers into the gap she had made. Bracing herself, she pulled with both hands and, with a slow sucking noise, the rock gradually came away from the wall. With a final sound like an egg being cracked open, it suddenly came free and she staggered back a couple of paces.
    "There!" she said triumphantly and held it up so he could see. It was roughly the size of half a football, and as she flipped it over, Will recoiled. The underside was leathery and pulpy, with a band of small filaments rippling at its circumference. It was an animal of some kind.
    "What the heck is it?" he said. "A giant limpet or something?"
    "I told you -- it's a cave oyster. They feed on the cinder algae around water holes. It tastes disgusting raw, but it's OK boiled." As she poked her thumb into the middle of the pulpy mass, it heaved and the animal began to extend a large, fleshy trunk, like the foot of a snail but many times bigger. Elliott stooped to carefully prop the animal upside down on its shell between two stones. "Should keep it from straying until we get back."

    * * * * *

    Their journey across the Great Plain was uneventful, although they were forced to cross several canals using the narrow lock gates as bridges. Will worked hard to keep up with Elliott, who moved at an astonishing speed. He practiced treading as she'd shown him, but it wasn't long before his insteps began to ache so badly he had to give up.
    She slowed as the cavern wall came into sight. Carefully checking the surrounding area with her rifle scope, she led him along the wall and into a low, wide tunnel. She stopped when they'd gone a few hundred feet.
    A wall of smell stayed them.
    There was the most intense reek of rotten meat -- sour blasts of it assailed them. Will tried to breathe through his mouth, but the horrific stench was so strong in the air, he could almost taste it.
    Then, through his scope, he caught something that made his heart skip a beat.
    "Oh no!" he gasped.
    On one side of the tunnel, there were the bodies of what, from their clothes, had to be renegades. On the other side, facing them, were Coprolites, still in their bulbous dust suits. Will knew instinctively that the Styx had been responsible, and that the corpses had been decaying for some time. The odor could mean nothing else.
    He counted five renegades and four Coprolites. The bodies in both ranks were on thick wooden stakes. The victims' heads sagged forward onto their chests, their feet supported by small timber crossbars nailed to the planks approximately two feet off the ground. This gave an eerie effect, as if the dark and silent bodies were actually suspended in air.
    "But why did they do this?" Will asked, shaking his head at the terrible loss of life.
    "It's a warning, and a show of their power. They do it because they're Styx," Elliott replied. As she walked down the line of renegades, Will stepped over to the Coprolites.
    "I knew this man," Elliott said sadly, standing motionless before one of the bodies.
    Holding his breath, Will made himself look at a dead Coprolite. The mushroom color of the suit showed up clearly in the amber of his night scope, but there was a darker texture smeared around the eye holes. The luminescent orbs were missing from them. It was evident that