Special forces soldier Jin Quan is betrayed during a mission and becomes a living target for a guided missile. When he wakes up again, he finds himself as a destitute man collapsed on the streets of Lower City.

Lower City is a gathering place for the lowest class of humans in this world, where people exist as disposable mining slaves. At the moment of life and death, Jin Quan awakens the Demon Swordsman class, and the radiation from the dirty bomb explosion in his past life becomes his talent.

In this world, Jin Quan will fight to the death against the Chosen Ones.