I found The Impossible Cube to have a nice mix of characters, settings, and story. The motivations for the characters may not always be the best, but each of the characters firmly believes in them, and that spills over into the "believeability" factor for me. That factor is also carried further by the flexibility of the characters and by that I mean that, while there are "good" and "bad" characters, they are, over all, characters with both good and bad sides to them.
What I liked about the settings is that they are "international" in that they cross several European borders and semi-historical events.
Which leads me to the story. The characters have an ultimate destination and are thrown into situations and by obstacles all along the way that may or may not keep them from that destination. How they deal with each situation makes for good reading.
The Impossible Cube is the second book in a series and, while The Doomsday Vault (first book) should be read first for continuity, I think it can be read as a stand-alone book.
Britain and China are superpowers and steam and brass inventions have elevated them to that position, Gavin Ennock - (airship) sailor of the skies and fiddler - has the clockwork plague, a plague that at once allows him to conceive mechanical wonders and consumes his intellect. Alice Michaels sought a cure for the plague because of Gavin and the British Empire declared them enemies of the Crown.
Accompanied by Gabriel "Dr. Clef" Stark (a clockworker), Feng Lung (son of China's ambassador to Britain), Kemp (mechanical valet), and Click (windup clockwork cat), Alice and Gavin head to China in search of a cure that would help Gavin. Even so, not everyone of these companions has the purest of motives and they are pursued by members of the Third Ward.
In an age where fantastic inventions of steam and brass have elevated Britain and China into mighty empires, Alice Michaels faces a future of technological terrors...
Once, Gavin Ennock sailed the skies on airships and enchanted listeners with his fiddle music. Now the clockwork plague consumes his intellect, enabling him to conceive and construct scientific wonders- while driving him quite mad. Distressed by her beloved's unfortunate condition, Alice Michaels sought a cure rumored to be inside the Doomsday Vault-and brought the wrath of the British Empire down on them.
Declared enemies of the Crown, Alice and Gavin have little choice but to flee to China in search of a cure. Accompanying them is Dr. Clef, a mad genius driven to find the greatest and most destructive force the world has ever seen: The Impossible Cube. If Dr. Clef gets his hands on the Cube, the entire universe will face extinction.
And Gavin hold the key to its re-creation...