Stalwart Victorian Inspector Ernest Lock (Dead Born, not reviewed, etc.) goes up against more killers than one in 1880 London.
The trouble begins with a letter to Scotland Yard from a correspondent calling himself Quicksilver and threatening to top the recent Hensworth disaster, a steam-engine explosion, at the forthcoming Metropolitan Annual Police Fete at Alexandra Palace. Even if it comes to naught, Lock ruefully acknowledges, the threat means endless pains for the police officers who’ll be diverted from their regular duty to head off possible trouble among the expected 40,000 revelers. But it doesn’t come to naught. As scores of observers watch uncomprehendingly, a middle-aged woman slides from her perch on the merry-go-round to become a bleeding casualty. And the repeated brainwaves Best and his friends have about where Quicksilver may have planned detonations—a series of mistakes Lock expertly milks for suspense—eventually do culminate in an explosion, with more promised in a series of letters from Quicksilver larded with increasingly cryptic literary allusions Best farms out to Helen Franks, the strong-willed painter who refused his courtship but remains his friend. Even so, the biggest riddle here isn’t the identity of Quicksilver but of Best’s true love, a question that appropriately provides Lock with a climax more powerful than anything that’s come before.
Best’s third case is a middling period procedural most likely to appeal to readers who’d like to see Victoriana get blown up.