David Holden, a modern chief military industrial designer, travels to ancient times and becomes a beggar after a lab explosion. The Emperor arranges for him to marry the three daughters of the Chancellor's Whitman Family: Nancy Whitman, Elsie Whitman, and Claire Whitman.
When the Whitman family is wrongfully framed, the four of them are imprisoned. There, David unlocks a space with a quantum printer and gains access to modern weapons.
After escaping prison, they use technology to fight off pursuers, build a new city, win popular support, and defeat villains such as Elliott Monroe and Frank Hawthorne.
Facing the Imperial Guard and Grandmasters sent by the Emperor, David crushes them with mechs, missiles, and other advanced weapons. He exposes the Emperor's crimes, finally eliminates the tyrant with a black hole cannon, and purges corrupt officials.
He refuses to ascend the throne immediately and instead prioritizes stabilizing people's livelihoods. Together with the three Whitman sisters, he embarks on a new era of governance.
