Seo Jin, the only ordinary boy from a family of kung fu masters. One day, he accidentally gets caught up in a fight between the villainous Traffic Light Trio and the hero Captain Charming, falling into a desperate crisis. Suddenly, a spaceship falls from the sky, and from it emerges a cute jelly alien named Hei! Claiming to have appeared for the birth of a great hero, Hei forcibly merges with Seo Jin, appointing him as his partner and hero... Thus begins Panty Man's chaotic hero life!