Esper of the Foreign Substance in a World Without Guides

S-Class Esper, Na Yu-seong, one day falls into an unidentified portal with his guide, Ji Seon-woo, and is transported to a new world. Picked up by a man named Zayan, the two are asked to save a 'future world without guides.' Na Yu-seong, who only wants to return to his own time with his guide, refuses, but unlike him, Ji Seon-woo accepts to save the world... "What are you trusting and staying here for? Who knows what those bastards will demand! Snap out of it, we've been kidnapped! We're victims!" "I know that! But what if we go out without a plan? What are we going to do out there? What if it's more dangerous than here, if there's no food or place to sleep?" In the end, Na Yu-seong...