In the wake of a catastrophic global disaster that has left the outside world infested with menacing threats, three young survivors—Axel, Jonatan, and Ana—isolate themselves inside a heavily fortified house converted into a concrete bunker. Cut off from reality, they manage their daily survival through strict house rules and private video diaries. However, the claustrophobic confinement completely fractures what was once a harmonious, intense polyamorous love triangle. With Ana and Jonatan now pairing off as exclusive lovers, a bitter atmosphere of unrequited desire and jealousy forms under the roof. The toxic domestic friction reaches a volatile breaking point when, following a reckless dare, they capture a living specimen from the outside and bring it into their home, systematically dismantling their fragile psychological walls.