England, 1882. Evelyn is bored with society and its expectations. So when her beloved sister, Rose, mysteriously vanishes, she ignores her parents and travels to London to find her, accompanied by the dashing Mr. Kent. But they're not the only ones looking for Rose. The reclusive young gentleman Sebastian Braddock is also searching for her, claiming that both sisters have special healing powers. Evelyn is convinced that Sebastian must be mad, until she discovers that his strange tales of extraordinary people are true—and that her sister is in graver danger than she feared.