"When the bell falls silent...the nightmare begins" : On a normal school day, Mary smuggles her phone into school, not knowing that one text message will turn their world upside down. It all starts when her teachers are suddenly late, worrying the students. Suddenly, her senior classmate Jason shouts, "Zombies have taken over the world! All the adults are dead!" The school turns into a last resort. A mysterious helicopter lands loaded with food and weapons, with a stern warning: "Choose leaders... or prepare to perish." Quickly,Ian, who has a strong physique, comes forward and the wise Aisha emerge to lead the fourth middle school, while the rest of the leaders remain mysterious. In the dark of night, while on guard duty, Mary hears a faint moan. Using her intuition and intelligence, she saves a classmete who is dying of an Asthma attack. Her colleagues also notice her intelligence and strength. . This heroic act causes the third middle school students to choose her as their leader. But the real surprise awaits her in the leader's room, where three mysterious strangers appear: her childhood friend, the Chinese genius Han Liang Xin, the strong and energetic American and Korean girl Fiona, and her mysterious twin Ethan, whose eyes hide dangerous secrets. The leader's are given many tasks outside the school walls and the students are taught to fight. The school is now a survival zone. The zombies are outside, but the real danger may be among the captains themselves. Betrayal, fragile alliances, and deadly missions outside the walls. In a world dominated by death, will the captains survive... or will darkness swallow them?