World War I looms on the horizon. Beneath the airship- and flying-bicycle-filled skies of London, Peregrine Gallagher, apothecary clerk, labors on a device he calls a Visualiser - a computer interface decades before its time. The goal is to link Britain with "the Hun" in real-time via a colleague in Cologne and, in addition to making them both wealthy, stave off the war. If people can see that they're more alike than different, why would they let their leaders compel them to fight?In any event, Peregrine hopes his sometime lover, Lady Euterpe Gosling, whose husband is a diplomat, will be impressed enough by the Visualiser to become his patron. His work is interrupted by the abrupt arrival through a broken window of a frightened ginger cat who, as he watches, transforms into a freckled ginger girl. Or is it the other way around?While Euterpe is in Southampton watching the unsinkable Titanic sail, Peregrine draws out Xenia's story - of running away from a workhouse in Wales to adoption by a clan of Irish Travellers to a cruel accident that left her on the cobbles of London. But she's never turned into a cat before.Peregrine realizes a shapeshifting cat hiding behind the draperies would make a perfect spy, and presents her to Euterpe. If Xenia can learn to channel her shapeshifting, Euterpe can offer her an unimagined adventure as her traveling companion, from the conference halls of Berlin to the salons of Paris. Xenia wants one thing in return - for Peregrine to build a device that might save the life of someone she loves. Ailuranth serves up a little bit of cyberpunk, a background of alternate history, a generous dollop of magic, brief appearances by Lincoln, Churchill, and Bertrand Russell, not to mention a talking Octopus, and asks the question: Can a small ginger cat change the course of history?