Indigo de Vargas is determined to exhibit her products at the Great Exhibition in Crystal Palace. Her opponents have thwarted her preparation at every turn. Her only hope is the brooding captain who appears on her doorstep in the midst of a fierce snowstorm offering to navigate her submarine to the Amazon so she can collect the passionflowers for her pharmacologicals and cosmecuticals.
Steam powers more than the submarine on this voyage. Sparks flying between Indigo and her captain may ignite a passion neither can avoid. Ably assisted by quirky servants, brass goggles and inappropriate accoutrements, they must fight those out to foil her mission.