Luck in the Shadows

The keep backed directly onto the cliffs; from where they stood, there was a sheer drop into the shadowed river gorge below.
    "Caught in a high place again," Alec whispered nervously, hanging back.
    "Not caught yet. Here's what we want," said Seregil, poking around in the shadows under the north wall, where the glow of his lightstone revealed another door. Scarred and weathered as it was, it, too, had a stout lock and hinges in excellent repair. Beyond it, a curving staircase spiraled down into darkness.
    Seregil felt a familiar tightness in his belly as he peered down. "This place is dangerous—I can feel it. Draw your dagger and watch your footing. Keep count of the steps, too, in case we lose our lights."
    The steps here were smooth but narrow underfoot, reminding Seregil of those leading down to the Oracle's chamber beneath the Temple of Illior. The curve of the smoothly dressed walls sliced away the view fifteen feet below at any point. Rusty iron sconces set into the stone at regular intervals held thick tallow candles, but these were dusty. The whole place had an abandoned, disused smell.
    Counting softly to himself, Seregil moved down the steps with a wary eye out for trouble. Fifty-three steps down, something caught his eye and he held up a warning hand. A length of blackened bowstring had been fixed tautly across the next step a little above ankle height.
    "That could give you a nasty fall," Alec muttered, peering over his shoulder.
    "Worse than that, maybe," replied Seregil, squinting into the shadows below. Taking off his cloak, he shook it wide and cast it out in front of him.
    It floated down a few feet, then caught on what appeared to be another string stretched at an angle across the stairwell. Examining it, they found it to be instead a thin, rigid blade.
    Seregil tested the edge of it with a thumbnail.
    "Fall just right and this could take your head off, or an arm."
    They found three more pitfalls of similar design as they continued down. Then, rounding a final turn, they came to the top of the rubble pile blocking the first entrance.
    "This doesn't make any sense!" Alec exclaimed in frustration. "We must have missed something."
    "We found exactly what we were meant to find," Seregil muttered, heading back up the stairs.
    "It's another diversion, too obvious and too dangerous. It does prove one thing, though; this tower is in perfect repair. They're hiding something here for certain."
    Toiling back up the stairs, they came out again on the rampart.
    "We have to work fast now," Seregil warned, glancing up at the stars, which had wheeled noticeably to the west already.
    "What if the real way in isn't here?"
    "That's a distinct possibility." Seregil ran a hand back through his hair. "Still, everything we've found so far tells me that this is the place. Look around, check every stone. You start there, at that corner. I'll begin here. Look for uneven stones, listen for hollow spots, anything. We're running out of time."
    Shielding his light, Alec crossed back to the ruined wall while Seregil remained in the shadows near the door.
    Despite Seregil's confidence, Alec renewed his search with little expectation of success. The mortar was sound, the stones solidly set together. Crossing back and forth, he checked and double-checked his section without finding anything new, and all the while the moon sank lower.
    He was crossing to the northern parapet when his bare foot struck a slight declivity he hadn't noticed before. If he'd had his boots on he'd have missed it entirely, but the loose grittiness beneath his chilled toes felt distinctly different from the surrounding flagstones. Dropping to his knees, he found what
    appeared to be a patch of sand slightly larger than the palm of his hand.
    "Seregil, come here, quick!"
    With Seregil hunkered down beside him, Alec scooped out the sand and uncovered a square niche sunk into the stone. At the bottom lay a large bronze ring fastened loosely to a staple. It was large enough for him to get a good grip and he pulled up hard, expecting the resistance of a heavy slab. Instead, an irregular section of thin flags lifted easily, revealing the square wooden trap door fastened to their underside. Holding their lights down, they found a square shaft, with a wooden ladder leading down to yet another door.
    "Well done!" Seregil whispered. Descending the ladder, they pulled the door closed over them.
    The door at the base of the ladder had no lock, just a curved latch,