Now I really have to marry the princess.

In a sudden turn of events, a college student finds himself transported to the fifth year of the Zhenguan era, where he must navigate the complexities of ancient Chinese society. With no other options available, he decides to marry a princess, hoping to help his kind-hearted brother-in-law, appease his hypocritical father-in-law, and manage a group of unruly brothers-in-law, as well as soothe a host of difficult sisters-in-law. As he becomes embroiled in the intrigue of the Tang Dynasty, the atmosphere of the era undergoes a significant transformation, setting the stage for a fascinating tale of politics, family dynamics, and self-discovery.