The manga is about Yeon-woo, who had a twin brother who disappeared five years ago. One day, a pocket watch left by his brother returned to his possession. Inside, he found a hidden diary in which was recorded “By the time you hear this, I guess I will be already dead….”
His brother had decided to explore Obelisk, the Tower of the Sun God, a world where several universes and dimensions intersect. While in that world, his brother had fallen victim to betrayal. After learning the truth, Yeon-woo decided to climb the tower along with his brother’s diary.