Su Wan, an ordinary high school student, accidentally traveled to the world of "Slayer of Gods" and became Lin Qiye's deskmate. However, she found herself trapped in a strange time loop - every 49 days, she would return to the day she transferred to another school and experience the same plot over and over again. What shocked her even more was that a Klein blue butterfly pattern appeared in the depths of her pupils, which was exactly the same as the pattern of the Night Watch emblem.
In the seventh cycle, Su Wan awakened the "Eye of Truth" and could see etheric threads invisible to ordinary people. She and Lin Qiye jointly investigated the ruins of ancient gods underground on campus and discovered a mysterious altar built by missionaries in 1894. The star map floating on the wall and the suspended Klein blue butterfly amber seem to be closely related to her travels and cycles.
As the investigation deepened, Su Wan discovered that she was actually the vessel for the resurrection of the ancient god, while Lin Qiye burned his black eyes to expand the forbidden areas of the gods, just to help her gain seven seconds to reverse the cause and effect. When the Klein blue butterfly completely merges into her pupils, Su Wan must make a choice between self-annihilation or releasing the "Key to the Door".
