Jin Feng, a modern engineer, reborn in Great Kang Dynasty. Weds Guan Xiaorou, shunned as bad-luck omen. Uses modern knowledge to build crossbows, upgrade spinning wheels, set up textile workshop, befriends Qing Huai, a marquis. Eliminates local bandit threat. At frontier, deploys anti-horse pits and battle formations. Crushes Dangxiang cavalry at Qingshui Valley, earns military merit. Yet court infighting leaves him with an empty honorary title of Baron.