Tunnels 02, Deeper

friend.
    "Sorry, I don't agree," Cal said, cutting across their banter. "If this is some sort of food store, we may be close to a Coprolite village."
    "Yeah, and...?" Will challenged.
    "Well, your so-called father... he's going to be on the lookout for food, too." Cal reasoned.
    "True," Will agreed.
    They walked a little farther, their feet kicking up dust, until Cal announced in a singsong voice: "It's getting stronger."
    "You know, I think you're right. There is something," Will said as they drew to a halt, sniffing.
    "Hmmm, a fast-food place, maybe?" Chester suggested wistfully. "I'd give my little finger for a supersized Mac Meal right now."
    "It's like something... sweet," Will said, a look of intense concentration on his face as he took a further succession of deep sniffs.
    "Whatever it is, let's not bother," Chester proposed. He became nervous, darting cautious glances around him so that he appeared a little like a strutting pigeon. "I really don't want to meet those Coprolite things."
    Cal turned to him. "Look, how many times do I have to tell you? They're completely harmless. People in the Colony say you can take what you like from them, if you can find them in the first place."
    Since Chester didn't make any sort of response, Cal continued. "We have to investigate anything unusual. If we've noticed it, Will's father might've, too, and that's what we're sort of here for, isn't it?" he finished sarcastically. "In any case, we had to stay on this side of the canal because you didn't want to get your feet wet." Cal bent to pick up a stone, which he threw aggressively. It hit the water with a loud splash!
    "You never let up, or shut up, do you?" Chester groaned.
    "Oh, yeah?" Cal replied.
    "Well, it's funny, but I didn't see you stripping off and jumping in the canal headfirst." Chester glared at the younger boy. "What's the saying -- lead by example? "
    "What do you mean, lead? We don't have a leader; we're all in this together, remember?"
    "Could've fooled me."
    "C'mon, guys," Will pleaded. "Knock it off. We don't need this."
    The trio lapsed into an aggrieved silence as they set off again, the bickering between Cal and Chester suspended for the moment.
    Then Cal peeled away from Will and Chester, taking a route perpendicular to the canal.
    "It's coming from over here."
    He stopped as the beam of his lantern caught a rocky outcrop. Next to this was an opening, a naturally formed slit in the ground, like a large letterbox.
    As the other two peered into the opening, Will happened to catch sight of a cross staked into the earth by the side of the outcrop. The cross was fashioned from two pieces of wood, bleached as white as bone and somehow bound together.
    "What does that mean?" he asked, pointing it out to Cal.
    "Bet it's a Coprolite marker," his brother replied, nodding enthusiastically. "If we're in luck, there could be a settlement down there, and they're certain to have some food. We can help ourselves to all we want."
    "I'm not too sure about this," Will shook his head.
    "Will, let's just forget it and keep going," Chester urged his friend, staring into the hole apprehensively. "I don't like the look of it, either."
    "You don't like the look of anything ," Cal spat at him. "Why don't you stay here while I take a look," he said, and scuttled down into the opening. After a few seconds, he shouted up to them that he'd found a passageway.
    Will and Chester were too weary to say anything to stop him, knowing full well they'd get into another fight. With reluctance, they both followed him in. Clambering down, they found themselves in a horizontal gallery. Cal hadn't waited for them and was already some distance farther into it. They went after him, but it wasn't easy going. As the gallery pinched down to a small passageway, Will was forced to dump his backpack, next to where Cal had already shed his.
    "I hate this," Chester groaned. Both he and Will were breathing hard as they pulled themselves along, sometimes dropping onto their chests to squeeze through the places where the passage ceiling lowered.
    Chester was struggling. Will could hear his friend's labored breathing as he wormed his way along. He still hadn't recovered from the months of incarceration in the Hold, despite the brief rests on the Miners' Train and at the old Styx house.
    "Why don't you turn around? We'll meet you back at the entrance," Will suggested.
    "Nah, it's OK," Chester puffed, grunting with the effort as he forced himself through a