In "The Sign of the Stranger," Le Queux likely crafts a tale involving mystery and suspense, with the title suggesting the presence of an enigmatic or unknown character whose actions or identity drive the narrative forward. The novel may explore themes of secrecy, hidden identities, and perhaps an unfolding conspiracy that the protagonist must unravel.Given Le Queux's expertise in writing thrilling and fast-paced narratives, the plot probably includes a series of dramatic events, unexpected twists, and a blend of detective work and adventure. The story might involve the protagonist encountering a series of clues or symbols (the "sign") that lead them deeper into the mystery surrounding the stranger.