Ever since Newton witnessed a bubble rising from his bathtub, mankind has sought the stars. When William III of England commissioned Capt. William Kidd to command the first expedition to Mars in the late 1600s, they proved that space travel was both possible and profitable. Now, one century later, a plantation in the flourishing British colony on Mars is home to Arabella Ashby. A tomboy who shares her father's deft hand with complex automatons. Being raised on the Martian frontier by her Martian nanny, Arabella is more a wild child than a proper young lady. Something her mother plans to remedy with a move to an exotic world Arabella has never seen: London, England. Arabella soon finds herself trying to navigate an alien world until a dramatic change in her family's circumstances forces her to defy all conventions in order to return to Mars in order to save both her brother and the plantation. To do this, Arabella must pass as a boy on the Diana, a ship serving the Mars Trading Company with a mysterious Indian captain who is intrigued by her knack with automatons. Arabella must weather the naval war between Britain and France, learning how to sail, and a mutinous crew if she hopes to save her brother from certain death.

Arabella’s wedding plans to marry Captain Singh of the Honorable Mars Trading Company are interrupted when her fiancé is captured by the French and sent to a prisoner-of-war camp on swampy Venus. Now, Arabella must find passage to an enemy-controlled planet in the middle of a war, bribe or fight her way past vicious guards, and rescue her Captain. To do this she must enlist the help of the dashing privateer, Daniel Fox of the Touchstone and build her own clockwork navigational automaton in order to get to Venus before the dread French general, Joseph Fouché, the Executioner of Lyon. Once on Venus, Arabella, Singh, and Fox soon discover that Napoleon has designed a secret weapon, one that could subjugate the entire galaxy if they can’t discover a way to stop Fouché, and the entire French army, from completing their emperor’s mandate.

Taking up almost immediately after the great Battle of Venus, Arabella has finally returned home to Mars to settle in to life with her husband, the mysterious Captain Singh. The Regent of the United Kingdom sets his eyes on solidifying his rule in the colonies and dispatches a fleet to better cement his control over Mars. Now Arabella and Singh must decide where their ultimate loyalties lie, with the Empire or with their home.