A pocket watch reaches Yeon-woo carrying his lost brother's hidden diary after five years of silence. Inside lies a chilling confession: "By the time you read this, I'm already dead." His twin didn't disappear—he was murdered by betrayal deep within Obelisk, the Tower of the Sun God. This legendary tower exists where universes and dimensions converge, a brutal realm where climbers pursue ultimate power. Yeon-woo's brother fell to its treacherous depths. Now, armed with the diary and burning for truth, Yeon-woo enters the tower himself, determined to climb higher and uncover what destroyed his twin. "From now on, I am Jeong-woo Cha." With his brother's name and legacy as strength, he begins his ascent.