When Joe Tournier steps off a train from Glasgow in 1898 Londres, he can remember his name but very little else, and he barely recognizes his surroundings. He learns that the former British capital has been a colony of the French Republic ever since France won the Napoleonic Wars 90 years ago. So begins Natasha Pulley's The Kingdoms, a deliciously transgressive work of steampunk speculative fiction.

Joe is diagnosed with "silent epilepsy," the official name given to the visions and amnesia that sometimes afflict people in this world. Otherwise in good health, Joe is returned to the French family to whom he is enslaved and to his wife, Alice, none of whom he recalls. After several years and the birth of his daughter, Joe receives a postcard of a lighthouse in the Scottish islands with a message signed by "M." Most mysteriously, the note arrives almost a century after it was written.

Joe is determined to get answers about his identity as well as that of the card's sender. He returns to Glasgow, now the site of a simmering British rebellion, and then travels farther north where he discovers a portal that acts as a pass-through from one era to another. Finally, at the lighthouse, he meets Missouri Kite, a Royal Navy officer from 1807, and is drawn into a complicated plan to use technology such as telegraphs and steam engines to aid in the British fight against the French.

Along with a cast of characters that includes the real-life Admiral Lord Nelson, Joe and Kite race from Scotland to Spain, trying to sway the forces that led to France's victory. The butterfly theory, which posits that complex changes often originate from minuscule actions, plays out as Joe ricochets from century to century, trying to help his friends and ensure his own future existence and that of his family.

Pulley balances the topsy-turvy nature of time travel by grounding her story in tidbits of naval history and a gradually unfolding queer love story.

Pulley's latest genre-bending feat (after The Lost Future of Pepperharrow) masterfully combines history, speculative fiction, queer romance, and more into an unputdownable whole. In 1898, Joe Tournier finds himself in Londres­­—a city in the French Republic, which colonized England in the Napoleonic Wars—without any memory of his life before that moment. All he has are hazy images that come to him in dreams and an unshakable sense that something is wrong. And he's not the only one: others in the city are feeling the same strange amnesia. When a postcard arrives for Joe bearing clues to his identity—mailed in 1805 but somehow depicting a recently built Scottish lighthouse—Joe resolves to find a way to reach that lighthouse and search for answers—but the mystery only grows more complicated from there, leading Joe down a rabbit hole that sends him from Scotland to Spain on a time-bending journey that spans more than a century. Pulley doesn't shy away from the story's sharp edges, exploring the devastating effects changes in the past can have on the future and shining a light on the ambiguous moral choices made by characters under duress. These dark, challenging moments are bolstered by the action-packed and intricate plot and leavened by the rich emotional entanglements of the makeshift family that Joe stumbles into along the way. This is a stunner. Agent: Jenny Savill, Andrew Nurnberg Assoc. (May)