The Havoc Machine

In this steampunk adventure by the author of The Dragon Men, a femme fatale offers a vengeful vigilante a simple job that becomes deadly.
The Clockwork Plague continues to incite destruction throughout the world. For Thaddeus Sharpe, the only solution for the disease is death. That is why he has dedicated his life to hunting and killing Clockworkers, and his mission brings him to the streets of St. Petersburg. There he meets a mysterious young woman named Sofiya Ekk, who offers him a proposition from her powerful employer, Mr. Griffin. Thad has his suspicions, but it's an offer he cannot refuse.
In a nearby village, a mad Clockwork scientist named Mr. Havoc has taken residence in a castle. His dreadful experiments on men and machine terrify the locals. He has created a dangerous machine, a ten-legged robotic spider. Griffin doesn't care what happens to Havoc; he only wants the invention. Simple enough...
But when Thad arrives at the castle with Sofiya, they make a startling discovery. Not only is Havoc hiding the machine, but he has also been experimenting on a little boy. Now Thad finds himself caught in a mystery he must quickly unravel before havoc reigns...
Praise for the Novels of the Clockwork Empire
"Action, adventure, dirigibles, and mad scientists, oh my!" - Night Owl Reviews on The Impossible Cube
"Harper creates a fascinating world of devices, conspiracies, and personalities.... Harper's world building is well developed and offers an interesting combination of science and steam." -SFRevu on The Doomsday Vault
"My favorite book in the series yet. I'm not sure whether that's because I've become so enamored with the world of the Clockwork Empire as a whole, or that the action sequences are nearly relentless, which a definite plus in this case." - That's What I'm Talking About on The Dragon Men