Tunnels 03, Freefall

she unbolted the door and flung it open. As she took a step through the opening, her crossbow was trained on something, and she looked tense.
    "What could have rung the bell like that?" Will pondered. "Spider-monkeys?"
    "Shh!" Chester hissed. "I think she's talking to someone."
    "Martha never stops talking," Will replied. "Even if there's no one there."
    "Will!" Martha suddenly cried out. "Get down here! Somebody's asking for you."
    The boys exchanged bemused looks.
    "Says she's your sister," Martha added.
    "Jesus Christ! I don't believe it!" Chester exploded, thumping the doorjamb. "Your bloody sister! Those foul murdering cows have followed us here!" He turned and dashed inside the shack, but Will was already making his way down the path to the main gate, racked with curiosity, and dread.
    Martha didn't look up from her crossbow, her lips tight as she spoke. "Know her?"
    Will poked his head cautiously outside the doorway.
    It was Rebecca!
    One of the twins was standing there, her hands clasped before her and her fingers interlocked. Her face was streaked with filth and shiny with tears.
    "Oh, Will," she croaked as soon as she saw him. "Help me. Please... please help me."
    Will was speechless.
    "She's wearing a Limiter's uniform," Martha spat, her fingers clenched so tightly around the crossbow that her joints were white. "She's a Styx."
    Will found his voice. "Yes... a Styx. I told you she was a Styx," he said to Martha. Then he spoke to the Rebecca twin. "What is this? Why've you come here?"
    "Oh, Will," the lame twin pleaded. "You've got to help me. She threw me down the Pore."
    "Are you by yourself? Are there any other Styx with you?" Will demanded, as his brain kicked into gear. He scanned the gloom behind the girl. "Her sister might be here, or more Styx. This might be a trap," he said in a rush to Martha.
    With her crossbow still aimed on the girl, Martha advanced towards her. She stopped, then glanced quickly both ways along the tunnel. "Seems clear," she whispered.
    The Rebecca twin had shrunk back a couple of steps as Martha approached, and Wills aw that from the way she was moving there was something wrong with her leg. She also seemed absolutely petrified by Martha. She began to babble at Will. "I'm alone... she's not here... my sister... she threw me down the Pore."
    "On your knees, and put your hands on your head," Martha barked.
    "My sister... she... she pushed me down the Pore," the Rebecca twin continued to babble as she did what Martha told her.
    "Why would she do that?" Will asked.
    "I wouldn't go along with her any more. She's mad... I told her I wouldn't be part of it." Rebecca was crying openly now, her slim shoulders quaking. "She's just sick, Will. She made me do those things. She made me do everything. I had to -- she threatened to kill me, so many times." Her hands on top of her head, Rebecca peered up at Will, her raven hair scattered over her face.
    "You must think we're complete idiots!" Chester yelled. Will hadn't even been aware that he was there. "You lying little cow!" He was so crazed with fury that spittle was flying from his mouth as he yelled. Then he whipped up his rifle and aimed it straight at the kneeling girl.
    "No! Chester!" Will screamed, reaching for him. Will managed to knock the rifle just as it discharged. The bullet cracked against the rock somewhere behind Rebecca. Whimpering, she flung herself onto her side, her face buried in the dirt.
    Chester was working the rifle bolt so he could take a second shot. In the heat of the moment, Will pushed him hard in the chest. He was so surprised at Will's intervention that he relaxed his grip on the rifle, allowing Will to grab it away from him.
    "What are you doing? Give it back to me!" Chester demanded. He hunched his shoulders like a rugby player about to charge.
    "Steady, Chester," Will said, holding the rifle across his body, ready to fend off the boy if he had to.
    "She's a Styx," Will heard Martha growl. Will whipped his head around just in time to see what she was intending to do. Acting on pure instinct, he jabbed at Martha's crossbow with the rifle stock. It was enough to deflect the bolt, which swished into the shingle. It had missed the prone girl's trembling body by a whisker.
    "God! Both of you -- stop!" Will shouted. "Just stop!"
    Chester and Martha were both facing him now, and from their expressions he truly thought they might go through him to get at the Styx girl.
    "What's wrong with you? You nearly shot