The imperial physicians of the Tang Dynasty asserted that the frail and sickly Li Yue would not live past adulthood. Zhang Yang, who time-traveled across, simply refuses to yield to fate; he uses modern medical principles and dietary therapy methods to cure his little wife, and relies on planting rice, stir-frying tea, brewing wine, and opening shops to improve their life. Yet he never expected that his gentle and stubborn wife would actually be a princess of the Tang Dynasty; that cheap father-in-law who dropped by every few days, loving to brag and beg for tea, is none other than Emperor Taizong of Tang, Li Shimin! With their identities exposed, Zhang Yang can no longer avoid the imperial court and the world. With Tujue invading, Turkic forces moving in secret, an empty national treasury, and noble families placing constraints, he simultaneously cures illnesses to protect his wife and farms to make money, while battling aristocrats, teaching the crown prince, and offering strategic advice to the emperor.