Seniors at Seong-jin High School have worked their whole lives to write the CSAT exams in order to get accepted into a university. But just as their final year as high schoolers began, a war between humans and extraterrestrial creatures breaks out and every able-bodied persons up to the age of 24 are forced into conscription. Now, on top of 8 hour school days, they must also endure harsh military training so that they can protect themselves from the spheres. ⚠️BASED ON "Duty After School Part 1 & 2⚠️