▁of ▁web ▁man h wa ▁technique , ▁and ▁art istic ▁features . ▁ ▁Since ▁April ▁ 2 0 0 7 ▁this ▁man h wa ▁had ▁been ▁featured ▁on ▁Da um , ▁one ▁of ▁major ▁internet ▁port als ▁of ▁South ▁Korea ▁that ▁is ▁being ▁considered ▁a ▁birth place ▁of ▁many ▁hit ▁web to ons . ▁ ▁Plot ▁The ▁story ▁is ▁set ▁in ▁contemporary ▁South ▁Korea . ▁Some ▁ 3 0 ▁years ▁ago , ▁un ident ified ▁cre atures ▁appeared ▁out ▁of ▁now here ▁and ▁attacked ▁man kind . ▁They ▁caused ▁massive ▁destruction ▁wherever ▁they ▁went . ▁The ▁mon sters ▁are ▁called ▁" Tr ou bles ", ▁and ▁caused ▁the ▁world ▁to ▁fall ▁into ▁cha os . ▁Al ong ▁with ▁the ▁first ▁appearance ▁of ▁the ▁" Tr ou bles ", ▁some ▁number ▁of ▁humans ▁were ▁born ▁with ▁or ▁acquired ▁super natural ▁ab ilities . ▁These ▁mut ants ▁called ▁" Tra ces " ▁are ▁the ▁only ▁ones ▁who ▁can ▁fight ▁off ▁the ▁Tr ou bles . ▁The ▁Tra ces ▁are ▁also ▁considered ▁fre aks ▁and ▁generally ▁sh unn ed ▁by ▁the ▁community ▁because ▁some ▁of ▁them ▁mis used ▁the ▁powers ▁for ▁their ▁own ▁interest . ▁ ▁The ▁plot ▁revol ves ▁around ▁two ▁main ▁characters . ▁Sah ▁Gang - kw on , ▁a ▁high ▁school ▁student ▁born ▁as ▁a ▁" Trace " ▁who ▁attempts ▁to ▁hide ▁his ▁ability . ▁The ▁other ▁is ▁Kim ▁Y un - Se ong , ▁who ▁acquired ▁his ▁" Trace " ▁ab ilities ▁during ▁his ▁early ▁ 3 0 s . ▁So on