After spheres from the sky drop to the ground, military training begins for the students to ensure their safety. However, the students find it too demanding and have a difficult time. As students head to the shooting range to learn how to shoot, they get caught off guard and fall into a crisis. Meanwhile, a student gets killed by one of the spheres.
Elenco: Shin Hyun-soo , Kim Ki-hae , Lim Se-mi , Ahn Do-gyu , Kim Su-gyeom , Woo Min-kyu , Yeo Joo-ha , Ahn Da-eun , Lee Yeon , Kim Min-chul , Kwon Eun-bin , Moon Sang-min , Choi Moon-hee , Sohee , Ro Jong-hyun , Ji Min-hyuk , Yoon Jong-bin , Shin Su-hyun , Hong Xa-bin , Shin Hye-ji , Lee Soon-won , Shin Myung-sung .