A weak and sickly boy, Song Woo-moon's condition worsens when he loses his mental capacities, owing to a painting gifted by a sage. He grows up as the 'village idiot', pitied by his own parents. But unbeknownst to everyone, his life is about to change soon, and a new destiny awaits him. When Song Woo-moon turns 20, not only does he have an epiphany, but an undefeatable martial arts power begins to bloom inside the painting. What could all of this mean for Woo-moon? And what strange world awaits him?