A four-year-old little girl unexpectedly finds her way into the Duke Who Guards the Nation's mansion and becomes the beloved treasure of the entire family! Quirky, clever, and quick-witted, she repeatedly solves difficult problems with her remarkable abilities. Not only does she win the affection of her cold-faced young master father, but she also becomes the precious little darling cherished by the Old Madam. Once a quiet and desolate mansion, the household gradually comes alive with her arrival, bringing endless happy occasions and increasingly prosperous businesses. Facing outsiders' doubts and the many troubles within the household, the little girl always manages to turn danger into safety with her intelligence. Watch how this adorable little girl wins the love of the entire family through her own abilities and brings ever-greater prosperity and happiness to her household!