The air at the top of the Observatory was thin and biting, but no one felt the cold. All eyes were anchored to Theo's hand as he slotted the heavy iron key into the node Grandma Iko had pointed out. It fit with a precision that felt almost magnetic, the metal sliding home with a soft, oily click.
For a heartbeat, nothing happened. Then, the heavy timbers of the south staircase began to vibrate.
With a groan of massive weight being displaced, the entire set of stairs began to rotate. It wasn't a vertical movement, but a slow, sweeping arc as the staircase swung outward toward the terrace wall. The group scrambled back, watching in stunned silence as the wood and stone shifted with a rhythmic, mechanical precision. As the stairs cleared their original position, they revealed a hidden cavity in the floor—a dark stone passage that led to a massive metal door that seemed out of a bank's vault.
