The Whitby Mermaid has been stolen from Cruickshank's Cabinet of Curiosities and consulting detective Gabriel Wraith is on the case. And he's not the only one, for wherever there is a mystery to be solved, Ulysses Quicksilver is never far away. What does the theft of the mermaid have to do with the mysterious House of Monkeys? And what of the enigmatic criminal known as the Magpie? Ulysses embarks upon an adventure that takes him to Whitby where the mermaid was supposedly caught. But there are worse things awaiting him there than mermaids. The moors of Ghestdale are haunted by the savage Barghest beast, while in the abandoned mines beneath the Umbridge estate, abominations lurk in the darkness. And Ulysses Quicksilver is about to discover that the worst horrors are those spawned by Man's own selfish nature.