In 1990s Qinghe County, wealthy young master Lu Chang'an catches his girlfriend cheating with his best friend, only to be murdered by the pair and thrown into a river. Thanks to the Loyal Dog Family Protection System, he is reborn as a little yellow dog and adopted by Ye Qiuhe, the girl who once went to school with him. Using his unique canine abilities, he secretly investigates the truth, saves people to earn merit, and protects his family and the female lead. Time and again, he foils the villains' schemes to seize his family's businesses. After overcoming countless dangers, he finally accumulates enough merit to regain his human form and bring all the criminals to justice.