In "Destiny's Echo," Lu Xiaobai, an ordinary high school student, is suddenly attacked by "Xiao," a messenger from another dimension. On the verge of death, Xiaobai gains the ability to control time and is saved by his future self, "Cang." Taking over his deceased father's role, Xiaobai commands the Bureau of Demon Defense, a team focused on protecting humanity. With Cang and new allies, he faces various dangers from enemies, eventually finding and defeating them. His deeds alter the timeline and stop an approaching apocalyptic disaster for humanity.