In the year 1969, the Norwegian government made a groundbreaking announcement regarding the discovery of one of the globe's largest oil fields, located in the neighboring waters of the North Sea. This revelation initiated a thriving era of offshore drilling operations, predominantly manned by American teams, with the Norwegians lacking proper training to handle the complexities of such advanced rigs. Fast forward fifty years, and the repercussions of this oil boom begin to surface in alarming ways. A crack has emerged on the ocean floor, leading to the catastrophic collapse of an oil rig.
In the wake of this disaster, a dedicated group of researchers assembles to investigate the incident. Among them is Sofia, played by Kristine Kujath Thorp, an expert submarine operator. As she and her team embark on their urgent mission, they hope to locate the missing personnel and determine the root cause of the environmental mishap. However, what they uncover is the harbinger of a potential apocalyptic crisis. The emergency response is overseen by William Lie, portrayed by Bjørn Floberg, while Arthur, a colleague of Sofia's, is played by Rolf Kristian Larsen, and Berit, the safety operations director, is brought to life by Ane Skumsvoll.
Operating from the Normand Maximus, the team makes their way to the Ormen Lange rig, currently under development. As they navigate this perilous situation, William informs Sofia that minor subsidence beneath the rig's base is to blame for the devastating collapse. Armed with a mission to deploy her robotic devices, Sofia aims to ascertain whether there are any survivors trapped in the submerged rig's air pockets. Tragically, she discovers a man who is trapped but ultimately succumbs to the dangerous release of natural gas from an unknown source. Recognizing the severity of the gas leak, Sofia promptly warns the ship's captain to retreat; however, the gas detonates unexpectedly, resulting in a massive explosion that injures Sofia and forces her back to base.
At home, Sofia shares her life with Stian, played by Henrik Bjelland, who works on another oil rig and travels frequently for his shifts. Stian also has a son named Odin, portrayed by Nils Elias Olsen. Meanwhile, Arthur scrutinizes the footage retrieved from the robot submarine and comes to a chilling conclusion: the gas leak is not stemming from the rig itself but from the ocean floor below it. Her findings point to a possibility that the recent geological disturbances are not a mere subsidence, a fact that William recognizes but ultimately disregards.
William addresses the matter with a presentation to the Oil Minister, Steiner Skagemo, played by Christoffer Staib, revealing that the recent events could be linked to an ancient geological phenomenon stretching back 8000 years. This phenomenon involved the catastrophic shift of a massive shelf, displacing 5000 cubic kilometers of sediment underneath the ocean's surface. The shifting fault lines threaten not just the rigs, but also the surrounding environment.
In a bid to prevent potential disaster, William asserts the necessity of shutting down all wells and evacuating personnel until they can gather more information. The risk of an oil spill hangs heavily over the operations, with the memory of the Deepwater Horizon catastrophe fresh in everyone’s minds—one that was as large as Denmark for a single well, while the North Sea is home to 350 wells.
As preparations for evacuation get underway, one particular oil well, the Gullfaks, indicates an alarming error while closing down. Stian, alongside his team, takes on the responsibility of manually shutting it down. Soaring 138 meters beneath the sea, disaster strikes when the shelf collapses, sending shockwaves throughout the North Sea and demolishing 30 rigs in mere moments. Amidst the chaos, Stian finds himself trapped as his rig is compromised.
Desperate to save Stian, Sofia pleads with William for a rescue mission, but he stands firm in his decision, noting the slim chances of survival due to the unstable conditions. Nevertheless, Berit reports detecting movements at the rig's base, suggesting Stian could still be alive. Determined, Sofia enlists a favor and boards a helicopter, alongside Arthur, to reach the endangered rig equipped with a submersible.
Upon arrival, they deploy their robot to scan the area and, with a thermal camera, Sofia identifies a warm body curled up where she anticipated finding Stian. Meanwhile, the ocean floor fracture has severely ruptured oil pipelines, resulting in a disastrous spill spanning over 100,000 square kilometers. The consequences are dire, threatening the natural beauty along the entire west coast of Norway and potentially impacting nearby countries such as Denmark and Britain. In a difficult choice, William suggests igniting the oil spill while it remains concentrated to minimize the devastation.
In a heart-pounding twist of fate, Sofia plunges down the rig's intact pillar and manages to rescue Stian, who is miraculously still alive. During this critical moment, Skagemo speaks urgently with the Prime Minister and orders the igniting of the spill; Gullfaks, unfortunately, sits right at the center of the disaster. Berit informs William of Sofia's courageous attempt to save Stian, yet William’s fear grows as the flames are anticipated to reach them in a mere 5 minutes.
In a desperate bid for survival, Sofia fills a lifeboat with water intending to submerge it to escape the looming flames. As tension rises, the trio boards the lifeboat, only to find one latch stuck and preventing their launch. In an act of bravery, Arthur sacrifices his life to free the latch, enabling Sofia and Stian's escape just moments before the inferno engulfs the rig. With the lifeboat adrift, the absence of ballast causes it to sink momentarily.
Guided by Stian, Sofia locates the lifeboat's power supply, activates the ballast, and soon they resurface in safety, steering towards the shore. Their reunion with young Odin, who had been under Berit's care throughout this turmoil, marks a poignant moment, encapsulating a grueling ordeal that took a year before the smoke from the devastation finally cleared.
