In 1969, the Norwegian government announces their discovery of one of the world's largest oil fields in the neighbouring North Sea, launching a prosperous period of offshore drilling. 50 years later, the environmental consequences begin to manifest - a crack has opened on the ocean floor, causing a rig to collapse. A team of researchers, including submarine operator Sofia, rushes in to assess the cause of the damage, but what they discover is that this is the start of a possible apocalyptic catastrophe. As rigs are evacuated, Sofia's loving companion Stian becomes trapped in the depths of the sea, and Sofia must dive in to rescue him.