The factional system disintegrated, and Evelyn (Naomi Watts), the mother of Lao Si (Theo James), became the ruler of the world inside the wall. She used strong and strict armed forces to control the residents inside the wall and not allowed them to cross the line. But Tracy (Shailene Woodley) and Lao Si don't believe in this evil. They firmly believe that the future and hope belong to the world outside the wall. So, the two led Christina (Zoe Kravitz), Pete (Miles Teller) and Tory (Maggie Q) to escape the encirclement and finally reached the other side of the high wall. On the other side, the Gene Bureau took in Cuisi and her group. On the surface, it seemed that the Gene Bureau was playing the right side, but in fact, its leader David (Jeff Daniels) had great ambitions and hid a surprising secret.