When mysterious alien spheres start invading the world, high school students are called upon to join the world’s first war against extraterrestrial forces.

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-cheol, Kwon Eun-bin, Moon Sang-min, Choi Moon-hee, Kim So-hee, Ro Jong-hyun, Ji Min-hyuk, Yoon Jong-bin, Shin Su-hyun, Hong Xa-bin, Shin Hye-ji, Lee Soon-won, Shin Myung-sung, Hwang Se-in, Oh Se-eun, Kim Jung-Ran