Modern corporate slaves Su Niannian and beauty blogger Shen Jiaojiao accidentally time-travel together to the great Dai Dynasty. One becomes the Empress and the other is exalted as the Grand Princess. In public, they strictly observe court hierarchy and etiquette, but behind closed doors, they are modern besties who talk about everything. Armed with contemporary workplace and beauty industry mindsets, they descend to outsmart the harem, communicating with the secret code "bubble tea, thirty percent sweetness," and joining forces to outwit the scheming virtuous concubine and the rebellious prime minister. The black-bellied Emperor Xiao Heng watches coldly, seeing through their abnormalities yet choosing to protect them. While defusing endless palace intrigue plots, the besties assist the Emperor in suppressing rebellions, building careers side by side deep within the palace, and reaping precious friendship, family bonds, and romance.