Quicker than the Human Eye

Putting greater distance between himself and Henshaw with every upward step, the graceful Arowe arrives at the top of the slightly spiralling stairwell, only to discover yet another open doorway.

Looking in, he immediately notices that this level is brightly lit by dozens of magical shining crystals mounted in the stone ceiling. The tapering tower has narrowed considerably from its lower levels but this room is still relatively large, or it would be if it hadn't been diagonally bisected. A heavy masonry wall spans the entire length from floor to ceiling, but the roughly hewn blocks seem to be oddly cemented together with expensive copper rather than traditional lime mortar. More bizarrely, in the centre of the wall, and the room itself sits a huge, silvery ball, approximately eight-feet in diameter, with another, smaller one directly above it. 

Squinting, Arowe stares at the two asymmetric orbs. Initially they appeared to be pulsing in response to the overhead lights but after watching for a few moments, he begins to suspect that, rather than an orb, it's actually spinning rings moving so fast, they give the illusion of solidity. After a dozen more seconds, he's certain, with the smaller, slightly slower, one offering glimpses of some green crystal hidden inside.

Intuitively understanding the connections, the Elven Archer realises that, if he can dislodge the emerald in the top sphere, both spheres will slow to a stop, giving access to whatever's trapped in the larger one.

His theory is confirmed by the deeply etched message in the 'Common' script, stretching the upper length of the diagonal, stone wall, interrupted by the smaller spinning orb...

'If the Gem, you Snag... You may Free the Hag.'

Arowe's normally smooth forehead knots, as he considers this near impossible shot. To breach the tiny, spinning gaps with an arrow, he'd need to summon up all of his skill AND have the gods of luck smiling down upon him.

Puffing a little behind him, Henshaw catches up and cranes his long neck around the open doorway. He's proven himself to be a surprisingly clever fellow but his eyes are drawn, not to the spinning orbs, but the stone plinth the larger one sits on and a smashed display cabinet mounted on the wall in direct line-of-sight to it.

"Why's there a gutter running from beneath that big silver ball and what do you think was sitting behind that broken glass?"

Arowe pulls his concentration away from the almost hypnotic spinning orbs and looks instead to where Henshaw's pointing.

There is indeed a narrow stone trench running from a circular drain coming out of the stone plinth under the larger orb, slightly sloping and running along the length of the diagonal wall. It stretches from the central plinth to outer wall, where it seems to exit via the start of a small stone pipe. The stone gutter is stained inky-black with whatever used to flow there, but whatever it was, for whatever reason, it's flowing no longer.

Next, the sharp-eyed Elf looks across at the broken display case mounted on the wall beside him. Shattered glass lies in shards beneath the wooden frame and the dark green velvet inside sits empty. All that remains are the two bronze hooks and the indentation left by a thick chain and large, heart-shaped pendant.. 

A heart-shaped pendant that Arowe realises that he's seen before!