A group of four teenagers—Liz, Mike, Geoff, and Frankie—embark on an adventure that quickly turns into a nightmare. Seeking to escape their routine and experience something out of the ordinary, they decide to explore an old underground bunker that had been used as a shelter during the war. At first, the excitement of being away from home and the adrenaline of discovery are palpable; the thrill is mixed with the air of mystery that surrounds the place. However, as day turns to night, the fun transforms into fear when they realize they have no way out.
As the hours pass and the lack of food and water becomes critical, tensions among the friends rise, revealing dark secrets and buried grudges. Each of them copes differently with the claustrophobia and desperation, and paranoia begins to take hold of their minds. What seemed like a fun getaway turns into a test of loyalty and survival, where the true nature of each person comes to light.
As they fight for their lives and for the truth, the atmosphere becomes increasingly oppressive, bringing the characters to a point where the boundaries of friendship and trust are tested. As events unfold, a dark secret is revealed, forever changing their lives and the way they see the world.