Stranded outside her silo with a failing suit, Juliette Nichols races against time, stunned to find another silo nearby that could be her only hope for survival. Meanwhile, unrest brews inside her original silo as Bernard Holland rallies citizens to maintain order amid rising questions about their world. As Juliette faces unexpected dangers near the new silo, hidden truths about the silos’ origins and the world beyond begin to surface, deepening the mystery.

1979年10月26日，时任韩国总统的朴正熙被自己的亲信射杀，局势顿时波谲云诡。为调查此事，陆军保安司令官全斗光（黄政民 饰）被任命为联合调查总部部长，而这个天生反骨的男人趁机扩大自己的势力，拉帮结伙，培植亲信，狼子野心昭然若揭。为了牵制全斗光，参谋总长任命将军李泰信（郑雨盛 饰）担任首都警备司令官，以防肘腋之变。与此同时，全斗光感受到来自总长的威胁，于是纠集亲信密谋逮捕总长，试图先下手为强。谁曾想全的人马急于求成，在未能逼迫代总统签署逮捕令之前便展开行动。成王败寇，一旦失败就会成为韩国的叛国者。一不做二不休的全斗光索性揭竿而起。
而孤军奋战的李泰信，将秉承最朴素的信念与叛军展开对抗……

In a bleak dystopian future, humanity clings to survival deep underground within the confines of a colossal silo. Juliette, an engineer tasked with unraveling the mystery behind the death of a colleague, uncovers startling secrets that threaten the very fabric of their enclosed world.