There is no bigger scum of the earth than Lloyd Frontera. He is the eldest son, yet all he does is drink and intimidate others, depleting what little is left of his family's wealth. The Fronteras' knight, Javier Asrahan, is destined to become a renowned swordmaster, and Lloyd's family will face pitiful deaths as their entire land falls to ruin under insurmountable debt.

Though at some point Kim Suho was an average civil engineering student in Korea, he suddenly wakes up on a dirt road as none other than Lloyd, an ungrateful hooligan from the beginning of a book following Javier, the protagonist. While a sassy status window offers some clarity about his new identity, Suho is rather worried about his imminent downfall.

To avoid becoming a beggar—and ultimately lead a sweet and comfortable life—Suho decides to fix Lloyd's scumbag image. With his engineering expertise and magical construction skills boost, Suho introduces modern innovations and city developments to this medieval-like world, drastically improving the people's quality of life—all for a nice sum of money.