In an unexpected twist, a 29-year-old office worker named Kousaka Kou finds himself whisked away to a parallel universe with basic abilities at his disposal. Presented with the classic choices of sage, hero, or demon king, he defies convention and instead unlocks a mysterious skill. Armed with the power of "Build" and his enigmatic talent, Kou embarks on a new journey as an adventurer, forging his path in this unfamiliar realm.