Purple spheres infested the sky, many thoughts they were harmless. In the bustling halls of Seongjin High, senior students find themselves thrust into a battle beyond their wildest imaginations. Among them is Choi Hee-jin, a quiet introvert whose beauty and skills captivate her classmates. Their friendship and trust will be tested throughout their adventures. Will they survive or would they all succumb to the creatures tormenting them? Duty after school cast x fem reader