A necklace Mouse gifts Catherine turns out to be made of antique gold, found in a buried ship Mouse discovered by accident deep in 'The World Below'. When he shows Winslow and stone-worker Cullen, it leads to an unheard-of spell of raw greed among their fellow tunnel dwellers, especially when Cullen tries to claim the ship's treasure as his own for sale, until Catherine, Vincent and Father find a surprising resolution.