Glamourist Histories, book 2 : Glamour in Glass
Mary Robinette Kowal2012

In the tumultuous months after Napoleon abdicates his throne, Jane and Vincent go to Belgium for their honeymoon. While there, the deposed emperor escapes his exile in Elba, throwing the continent into turmoil. With no easy way back to England, Jane and Vincent’s concerns turn from enjoying their honeymoon…to escaping it.

Left with no outward salvation, Jane must persevere over her trying personal circumstances and use her glamour to rescue her husband from prison . . . and hopefully prevent her newly built marriage from getting stranded on the shoals of another country's war.