First in the series, The Alliance of Silver and Steam this promises to be a fun adult steampunk saga. Willan Lucius is a lesser demon, tied to the post of assassin by a more powerful demon. Lucius wears human guise and he's happier tempting married women and anything else where a dangerous character is an asset. But he knows that when his overlord beckons he doesn't have a choice. This NIGHTMARE IN STEAM is about to begin.

Lucius is rather foul-mouthed, but we'd expect that of a demon. He lives in the Victorian era, in Whitechapel of London. A new band of demon hunters is on the street, and he has been ordered to find them. London's clock workers' guild is a front for the Alliance of Silver and Steam, and Lucius needs to kill one to steal his dreaming memories. Instead he makes a connection with a woman called Eliza Dorley, who attracts him sexually. Now he's in trouble.

Eliza is an inventor for the guild, creating everything from alarm clocks to ray guns for killing demons. She uses crystals as a power source and has even made an automaton shaped as a dog. The sudden death of one of the guild's young members shakes her to the core. This looks as though a demon has found them, and how can they be safe when they need to sleep?

Some of the concepts are fun like steam and clockwork motor bikes, while Eliza can't lace her corset by herself so the practical lady has made one with metal snaps in the front. Meanwhile we have to master the angel and demon concepts too. Seraphina has managed to rise to control the demons; a fallen angel herself, she has no liking for humans and wants to enslave this weaker race. There are various types of demon, from kappa demons to incubus, some in positions of human society's power, but as they are slow to reproduce the demon hunters could make serious inroads on their numbers. Seraphina wants the hunters dead.

Lucius has sex on the brain, or on other parts of him, continually, and with occasional graphic fight scenes and strong language NIGHTMARE IN STEAM is definitely a book for mature readers. This is a tense adventure in an atmospheric setting, sometimes erotic and often steamy. Lexie Ostrow's next book in this series is to be called Bite of Silver.