Rie, a PR coordinator, arrives at a tunnel boring machine to showcase the seamless collaboration behind a Metro construction project. However, tragedy strikes when an unforeseen accident traps her underground. Seeking safety, she finds herself locked in an airlock alongside Ivo, a Croatian miner, and Bharan, a worker from Eritrea. As they navigate the harrowing situation, the trio must confront their fears and forge unexpected bonds to survive the chaos unfolding around them.