Three-year-old Princess Jinyang, little Sizi, is the apple of the eye of Emperor Taizong of Tang, Li Shimin. One day, while she was acting coquettishly with the Empress, she suddenly vanished out of thin air and appeared in the home of a modern youth named Jiang Nan. Faced with this adorable toddler claiming to come from Chang'an City, Jiang Nan didn't believe it at all at first. But when little Sizi tilted her head to call him "Xiao Nangjun", curiously looked at the cola and asked "is the black water angry?", and solemnly corrected him that he shouldn't make noise while eating, Jiang Nan was completely melted by this soft, cute little princess.