Cherie Priest's growing world of steampunk Americana expands a whole lot more in Dreadnought, the third book in her ongoing Clockwork Century series following Boneshaker and Clementine.

Mercy Lynch is a Civil War nurse. Although she, a Virginia native, works to save Southern boys in this never-ending war, her Kentucky-born husband fights for the North -- at least, until Mercy receives word that he has died of his wounds in the Andersonville POW camp. Her mood fails to improve when she gets a message that her estranged father is dying -- and asking for her -- in the Pacific Northwest.

Against her better judgment, Mercy begins a long journey by dirigible, steamship and train -- but in the hands of Cherie Priest, it's anything but a peaceful trip.

Things get dangerous when her airship is shot down over a fierce action between the blues and grays. A frantic retreat turns messy when the Dreadnought, the North's heavily armed and armored steam-and-diesel engine, screams into the fray with an armored mech suit that strides into the battle like Goliath. The South has its own metal Goliath, however, and soon the massive soldiers are battling it out even as Mercy flees for safety.

There's enough material there for at least a novel or two, but Priest is barely getting started. Once she finds herself boarding the Dreadnought, readers will find themselves embroiled in a tense, white-knuckled read that has a life of its own; it won't lie quietly on your nightstand, I'm warning you, but will scream out to be read.

And I haven't even mentioned the zombies.

Boneshaker introduced readers to a rich, complex world where the Civil War has raged for two decades and technology -- particularly in the military arts -- has outpaced the reality of our own 19th-century advancements. Clementine added a new layer of swashbuckling adventure to that world.

But Dreadnought is a whole new ballgame. Priest, already high on my checklist for contemporary fantasy, has thrashed out a story that I simply could not put down.

Well paced and endlessly inventive, Priest's latest novel has many threads woven into Mercy's story. Some, by themselves, could fill a book, but for Priest they are simply a small piece to add a bit of color here, a touch of detail there, a tiny mystery that she might not ever resolve. While some subplots wander off in other directions, Priest keeps her eye on Mercy -- and what a protagonist she turns out to be. Strong and capable, independent and, when required, downright fierce, Mercy is a character I hope to see again and again. And again.

Although there are a few references to events in prior books -- as well as a few familiar faces -- Dreadnought stands entirely on its own. I recommend enjoying all three, but Dreadnought is an absolute must-read.