London, 1883. Young telegraph operator Thaniel Steepleton returns home to his tiny apartment in Pimlico to discover an exquisite gold watch left on his pillow by a mysterious visitor. While he is trying to figure out how an unexpected expensive gift came to him, the watch saves his life - forcing the young man to leave the place, where in a moment there will be a powerful explosion that will destroy Scotland Yard and the neighborhoods around. So Taniel becomes embroiled in a police investigation.