Jin Xiaoman, the lowest-ranking koi, accepts a fortune-transfer bounty that promises "food and lodging included." Upon descending to the mortal realm, she discovers the client is a poor scholar plagued by bad luck. He rejects good luck, saying that fortune is a bill that collects interest according to its price. She then realizes the bounty poster is fake and that forced fortune-transfer is a death warrant. Meanwhile, the scholar is actually the Third Crown Prince of the Dragon Palace undergoing a mortal trial, and her body conceals the dragon blood he fed her a century ago. Amid a cause-and-effect spanning ten lifetimes, the two finally await a reunion in a small Jiangnan courtyard.