Opening in 1960s Poland, Aleksandra tells the extraordinary story of its eponymous heroine, an MI5 spy. While attempting to accomplish her mission during the opening of a new mine, Aleksandra finds herself caught in a series of catastrophic events that leave her trapped deep underground and entirely alone, or so it seems...

The story follows Aleksandra in her struggles - recounting her experiences and the terrifying discoveries she makes on her way through what is soon revealed to be not just a maze of mineshafts but an extraordinary subterranean world. Space and Time bend and warp in ways that bring together a cast of characters from different periods of history - all of them survivors like Aleksandra, all of them desperately searching for the daylight and a way back home.