Keiko Kurakake, a dedicated scientist at the Shibasato research institute, receives an unexpected call from Professor Yamazashi, a figure from her past experiments in human cloning. Intrigued, she agrees to meet him, only to be astonished by his youthful appearance, a result of the mysterious Cambrian factor. Determined to replicate the evolutionary phenomenon known as the Cambrian explosion in present-day humans, Professor Yamazashi harbors ambitions of becoming their ultimate creator and asserting dominance over the world.