A year after the rock-slide in Geiranger, geologist Kristian Eikjord is preparing to appear on a talk show, and is hailed as a hero for saving hundreds of lives in the disaster.Three years later.Idun is divorcing him and he is separated from their children, Sondre and Julia. Kristian is living in seclusion in the mostly rebuilt Geiranger, his family is living in Oslo. Idun has a new job as a hotel worker at the Radisson Blu Hotel Plaza.Julia comes to visit Kristian for a weekend in Geiranger. Disappointed by how little he tends to her, Kristian has Julia go back home. That night, she discovers a secret room in Kristian's house dedicated to the 250 fatalities of the tsunami. She confronts Kristian about this, who reveals he feels responsible for their deaths. Despite Julia's admonishment that she now wants to stay the weekend, Kristian still sends her home early, calling her distracting. Some time later, the death of a colleague in the Oslo Tunnel prompts Kristian to travel to Oslo to investigate the circumstances of his death.Upon arriving in Oslo, Kristian finds out that his colleague was killed by a collapse in the tunnel he was studying, and was studying seismic movement across Oslo and the surrounding area. Researching the incident further with the help of his colleague's daughter Marit, Kristian eventually comes to the conclusion that a major earthquake, up to a 8.5 on the Richter Scale, may soon hit Oslo, and that the collapse that killed his colleague may have been a precursor movement to that. His attempts to warn his family are mostly ignored. That night, a massive power outage takes out all the electricity in the city, and a seismic rift destroys the Oslo Opera House, and injures Idun, who had arrived to watch Julia's ballet recital. Believing it to be a coincidence, Idun chooses to stay in Oslo. After an argument, Idun orders Kristian to stay away from her and the kids until he gets help.Kristian's continued attempts to warn his family backfire, leading to his wife ordering him to never speak to her again. Kristian does however convince Sondre to leave college for a week to a safer place in the countryside. Determined to save his family, he picks Julia up from her ballet class early, and heads to the Radisson Blu skyscraper with Julia and Marit to try and convince Idun to flee Oslo with them, and afterwards they will go pick up Sondre. Finding Idun on the 41st story, he pulls a fire alarm to get her and everyone else to evacuate. Julia wanders into the building to find her father, with Marit in pursuit. As the elevator doors close, Kristian sees Julia on the other end of the room. Despite attempting to call out to her, the doors close and the elevator begins to auto-descend. Suddenly, the power goes out. Marit finds Julia on the balcony, looking in the distance. The reflection in the glass door behind Marit reveals a trail of smoke and explosions, caused by an approaching earthquake, heading straight for the hotel. Marit grabs Julia and runs inside as the first shock-wave from the quake hits, knocking Marit unconscious. The ceiling of Sondre's lecture hall collapses, killing the professor and several students, and injuring Sondre's girlfriend. Kristian and Idun's elevator rapidly drops down the shaft, knocking Idun unconscious and injuring Kristian.Some time later, Marit wakes, finding Julia tending to an injured hotel worker. Next to the Radisson Blu, the Posthuset building shifts and then collapses directly into the right side of the Radisson Blu, leaving the 41st story hanging precariously over the wreckage, everything below it destroyed. Following an aftershock, the building begins to tilt. Marit unintentionally lets go of the injured hotel worker's hand, and she slides down the floor and out of the window to her death. Marit loses her grip, and nearly suffers the same fate, but grabs on to the edge of the mounted bar, as Julia hangs on to a railing.In the elevator shaft, Idun and Kristian are climbing maintenance ladders to get to the top floor. Debris knocked loose by aftershocks ricochets down the shaft and mutilates Idun's leg, forcing Kristian to carry her. They arrive at an open elevator door near the 30th story, and attempt to use a severed elevator cord to swing across to the opening. Kristian succeeds, but Idun falls to her death. A devastated Kristian heads to the place where he last saw Julia, and finds her and Marit huddling behind the mounted bar. A final aftershock causes Julia to lose her balance, and she slides down the floor towards the broken window. Kristian jumps after her, and pushes her out of the way, knocking himself unconscious in the process. When he comes to, he finds Julia precariously balancing on a cracking window. Carefully approaching Julia, he manages to grab her before the window breaks, and with Marit's help, pulls her up. Together, they leave the hotel.Some time later, Marit enters her office to find it mostly destroyed, except for a picture of her as a child with her father. A reunited Kristian, Julia, and Sondre arrive at their old home in Geiranger by ferry.