In this parallel Victorian era, the British Empire is at the peak of the steam revolution, with mechanical gears and chimney smoke dominating city skylines. However, there is an undercurrent under the prosperity - the industrial revolution released not only productivity, but also forgotten ancient taboos and mysterious existences from other dimensions. "Sequence" is the world's classification system for mysterious power. Different sequences represent different paths of power, from "Truth Weaver" (Detective Sequence) to "Son of Steam" (Mechanical Sequence), to "Abyss Whisperer" (Mysterious Sequence) related to the Cthulhu Mythos and "Blood Crest" (Noble Sequence) that controls the power of blood, etc. Promotion requires taking special potions and completing dangerous rituals, while losing control means being swallowed by power and turning into an inhuman thing. London, this foggy city, is both the pearl of industrial civilization and the whirlpool of mysterious events.
