Synopsis：High schooler Dan (Jang Ju Hwan) is the last descendant of Dangun, the mythical founder of Korea's first kingdom. While he possesses otherworldly powers through his heritage, he's forbidden from using them, but he doesn't seem to mind – instead, he seeks to become the school's best errand boy, earning him the nickname "Number One" among his peers. However, when his family and loved ones are threatened, Dan decides enough is enough and unleashes his true strength to fight back, sparking the beginning of a battle between gods, demons, and their descendants to steal a powerful heavenly relic. Can Dan carve out his own legacy and protect the ones he holds close?