Century communication, the charm came into the world, the iron hooves broke the bones, and the minions and teeth bleed. In order to resist these murderous demons, humans forged their own armor, known as Kamen Riders, and formed alliances to defend the land against enemies. This organization, which brings together the elite and carries all the hopes of humanity, is the Knights' Alliance. After 20 years of bloody battles, countless martyrs built steel walls with their flesh and blood to keep those monsters out of the iron walls of the war zone. Finally, the enemy seems to have died down, and peace seems to have regained in the world. Twenty years later, a young man with amnesia joined the organization. He didn't know who he was, but he was able to accidentally match a knight system that had been hidden in the snow for more than ten years. He doesn't know how many secrets he has buried, how many ups and downs he has experienced, and how many people's expectations he bears, and what cruel conspiracy he implies. The battle was protracted, and the secrets were revealed one by one. At that time, no one imagined that the undercurrent would one day turn into a turbulent wave, swallowing up all the whitewashed peace. Under the alliance, it may be far from being as peaceful as the world sees.