Manman's mother tells Manman a bedtime story before sleep: the koi fairy Manman sneaks down to the mortal world to train, almost being braised by an angler, but is fortunately saved by Yan Ze, the eldest young master of the Yan family. After returning to the Dragon Palace, she is kicked by the Dragon King to be reincarnated, becoming the adopted daughter of the Yan family. The Yan family is plagued by bad luck, with the mother seriously ill and the company facing constant crises. Endowed with fortune, Manman quietly saves her mother's life and helps her eldest brother expose a business competitor's plagiarism conspiracy. The green tea adopted daughter Yan Chufan makes trouble everywhere, bribing the butler to throw Manman into the sea; unexpectedly, Manman's true form is a koi, and she is carried back by a sea turtle. The little koi vows to protect the whole family and make all bad people pay the price.