A modern-day office drone named Jiang Chen dies from overwork (996 schedule) and reincarnates as a flea—with only 60 seconds to live. He activates an Infinite Mutation & Evolution System. At the brink of death, he accidentally gets drawn into the Blood Pact Formation of Lu Qing Shuang, the Reincarnated Saintess—and forms a life-and-death symbiotic contract with her. Lu Qing Shuang, who suffers from severe OCD and extreme cleanliness obsession, initially despises this filthy, grime-covered flea.