An unsigned secret letter leads the ace commissioners of Kassel College, Chu Zihang and Caesar Gatto, to the depths of London's thick fog. The "Dragon Crown" mentioned in the letter and the ancient guardian oath of the Knights Templar quietly awakened at the bottom of the Thames River. When the two first arrived in London, they were intercepted and killed by dead men at the airport. As the investigation deepened, they discovered that the Knights had been internally divided - the Discipline Master Mordred tried to use the shackles of the "Crown" to awaken the "Heart of the Temple", while the former Discipline Master Sir Thorne, who sent the letter of distress, was trapped in the core of the maze.
Under the guidance of the silver-haired witch Victoria Pendragon and the mysterious information dealer "Nightingale", the two sneaked into the underwater clock tower, broke through the alchemical puppets and deadly mechanisms, but only found the beacon and warning left by Sir Thorne. Then at the Buckingham Palace dinner, they used an exquisite alchemical disturbance to lure Mordred away and broke into the "Heart of the Temple" holy place, only to find that Sir Thorne had been trapped in the energy sphere, and Mordred was about to wear the strange crown intertwined with bones and black gold. In the final battle, Caesar and Chu Zihang were forced into a gap in time and space. Caesar made a contract with a proud golden lion cub, while Chu Zihang entered into a soul symbiosis with a poisonous black cat who controlled the fire of shadow. Mordred's crazy counterattack dragged the entire maze to the brink of destruction...
When the two fell back to London in the real world, Victoria had taken them into hiding in Pan's Labyrinth Circus, but the pursuers were close behind. At the same time, the elders of the Gattuso family suddenly appeared and forced Caesar to return to Portofino, saying that the secret of the "Heart of the Temple" was far older than the legend of King Arthur - the crown shackled may be an ancient creation-level existence. The unfinished story stops at the moment when Caesar boards the return plane alone: the fog in London is still lingering, Sir Thorne's life and death are uncertain, the true purpose of the "Dragon Crown" is still a mystery, and is the hand extended by the family a shield or another prison?
Concept: A lone wolf and a lion learn to trust each other while fighting side by side, and each becomes a stronger version of themselves.