In the dark underground tunnel, a subway line became a cage that traps survivors.A single mother held her young son tightly, her heartbeat resonating with fear.She once thought that the hardships of life were just a burden of daily life, but at this moment, her courage and maternal love were being pushed to the limit - because in this ruined carriage, a monster was hunting for the remaining humans. She is one of the few people who are still alive, and her children are innocently involved in this nightmare.Every step may be the approaching of death, and every breath is filled with the desire to survive.She must be calm and strong, even if her heart is already on the verge of collapse. In the control room above the ground, engineers who were staying at their posts were racing against time to find ways to rescue them.Time is bleeding, hope is collapsing, but they know: deep in the tunnel, there is still life waiting for rescue. This is not only a escape, but also an extreme test of love, responsibility and human nature.