Set with the historical backdrop of an alternate 19th century Victorian London, the protagonist Zhou Mingrui finds himself having transmigrated into the body of Klein Moretti, a recent history graduate in Tingen City. Faced with perplexing mysteries and strange, supernatural events, he quickly realizes things are not what they appear.

Filled with cannons, battleships, steam engines, and factories, as well as divination, potions, tarot cards, sealed artifacts, and superhumans known as Beyonders, Klein finds himself the unwitting leader of a secret organization, known only to his followers as "The Fool". Join Klein as he becomes a Beyonder, advancing in power and uncovering the mysteries of the world.

(Taken from the Lord of the Mysteries English Wiki.)