A string of mysterious deaths has occurred, leaving all of the victims with a purple butterfly-shaped bruise. According to investigators, the victims have all died from a hypnotic suggestion. The police bring in renowned psychiatrist Toshiya Saga, who specializes in hypnotic cures, to help with the investigation. He is determined to solve the mystery, but is caught off-guard when the woman he is attracted to becomes a suspect in the investigation.

封印不死兽后4年，剑崎等人过上平凡人的生活。但在某天，不死兽再次出现，而且要活捉天音，假面骑士们因此重新投入战斗……

人工不死兽化成剑崎的模样，并复制了Blade系统，真剑崎与之战斗，不分上下。鉴于真假剑崎难分，橘和睦月无法出手相助，而这时始用了一个简单的方法分辨真假……