A Song of the Rhapsody of the Luo River from the Start, and the Commandery Princess Recruits Me into Her Residence

Cao Xuan transmigrates to the Great Xia dynasty and becomes a prince's live-in son-in-law thanks to his poem, Ode to the Goddess of the Luo River.

But being a live-in son-in-law isn't easy. The princess gives him a title, but won't share his bed.

So Cao Xuan brings out a whole collection of "family heirlooms": Tang poetry and Song lyrics, coal stoves, curved-shaft plows, horseshoes, blast furnaces for ironmaking, Arabic numerals...

From Jinyang to Shang'an, from the imperial court to the frontier, he turns a son-in-law into the ultimate cheat code.

"What? A great scholar from Qi wants to challenge me to a math contest?"

"String him up."

"What? The young master of the Su family wants to steal my wife?"

"Castrate him."

"What? A hundred and fifty thousand northern horsemen are about to breach Yanmen Pass?"

Cao Xuan grabs his blade and mounts his horse, then looks back at the red-clad figure atop the city wall.

"My lady, wait for me to come back."

There's no such thing as a son-in-law making a comeback. There's only a man using a thousand years of knowledge to win a way out for a city and the person he loves.