A thousand years ago, the young emperor Xiao Jin was framed by rebellious officials and sealed within a formation. Unexpectedly, he activated a spacetime channel, being transported to a rental room in a modern metropolis, and was mistaken by the green intern Xu Nuonuo as a roommate who came to co-rent, beginning a co-renting life. He also acquainted the beautiful female CEO Su Wanqing through chance, getting forced into a transnational heist case of national treasure cultural relics. Having gone through twists and turns, he finally thwarted the criminal organization's conspiracy, successfully safeguarding the national treasure. Who would have expected that this item is the key to open the spacetime channel? With the spacetime channel open, facing the emotional entanglements of the modern mortal world and the country and state of a thousand years ago, how will the young emperor choose?