Corporate slave Shen Ke wakes up to find himself transmigrated into a three-year-old child in the Sui Dynasty. His father dies in battle, and he is adopted by Li Yuan to become a study companion to Li Shimin. Recognizing that the child before him is the future emperor, Shen Ke resolves to hug his coattails tightly, asking only for a stable life. Yet young Li Shimin is mischievous and combative, Li Xuanba is intelligent yet frail, and strife within the Duke's estate is endless. Relying on modern knowledge and an understanding of history, Shen Ke studies and trains in martial arts, figures out how to make money, and strictly guards the secret of his knowledge of the future. As the turbulent late Sui era closes in step by step, he grows from a companion who only wanted to coast through life into someone deeply trusted by the Li family. With upheaval impending, can he protect those around him and rewrite the predetermined tragedy?