Lin Yinmo, a professor at the University of Traditional Chinese Medicine, accidentally traveled to a different world, changed his name to Kai Yin, and worked as a herbalist in the border town of Oak for three years. He just wanted to keep the medicine shop, medicine garden and a stable life, but because of the cold light shining on the century-old oak tree in the back hill, he was involved in the whirlpool of the Holy See, the Final Sect and the ancient seal. Saint Freya was ordered to investigate the case and initially regarded him as a suspect; Kai's zeroing technique hidden in his body can bring everything related to himself back to the original state. Zhong Zhen wakes up, the medicine shop is burned down, and the twin marks drag them into the same disaster. Kayn can zero out wounds, poisons, and imbalances, but he can't zero out choices, separations, and costs.
