Illegal experiments conducted by Datian Pharmaceuticals trigger a zombie virus outbreak, allowing an experimental subject known as Xiao Mihu to escape to Donglai Village. The Xie family, who run an unlicensed repair shop, accidentally capture Xiao Mihu and discover an astonishing secret: anyone bitten by him begins to grow young again. After Old Xie is bitten and his body starts aging in reverse, the family charges villagers for the chance to regain their youth. As Xiao Mihu remains with the family, he and Xie Yingzi gradually develop feelings for each other. Eager to steal the secret, Er Kui breaks into the repair shop one night. At the same time, the virus suddenly spirals out of control, and infected villagers begin attacking everyone in sight. When the Xie family is trapped, Xiao Mihu risks his life to save them. The survivors eventually discover that Old Xie, the first person to be bitten, has developed antibodies in his body, making him the key to a cure. One year later, the Xie family uses his antibodies to vaccinate the villagers. Xiao Mihu returns, and together they protect Donglai Village in the ruined world, finally beginning a peaceful new life.
