A modern teenager skilled in Traditional Chinese Medicine time-travels to the fictional Yu Dynasty, becoming the notorious playboy Li Jingan. Just as the Empress falls gravely ill, he answers the public notice to enter the palace, curing the Empress with his medical skills and rising to fame overnight to be enfeoffed as the Marquis of Qinghe. Using timeless poetry to stun the imperial court and poetry gatherings, he also invents two sharp tools: saltpeter ice-making and horseshoes, solving the problems of intense summer heat in the military and warhorse wear and tear. Facing court rivalries, secret revenge from nobles, a princess falling in love and bestowing a marriage, and various other trials, Li Jingan relies on his modern knowledge and clear-headed wisdom to navigate and protect himself, on one hand seeking justice for the people and on the other contributing to the development of Great Yu.