The plot revolves around the real-life events on the offshore drilling rig Deepwater Horizon, which exploded during April 2010 and created the worst oil spill in U.S. history. Mike Williams, an electronics technician, and his colleagues, including veteran driller Jimmy Harrell, are stationed on the rig located in the Gulf of Mexico. They are tasked with completing the drilling operation, which involves descending through thousands of feet of seawater and drilling into the earth's crust to extract oil. The operation is technically complex, fraught with danger, and requires precise execution to maintain the balance of forces and prevent disaster.

Tensions mount as the crew discovers the job has fallen behind schedule, leading to risky decisions pushed by BP executives onsite. Harrell confronts the BP representatives over issues regarding the safety and reliability of the rig, particularly the concrete foundation that seals the well. Despite these concerns, they are pressured to proceed with the operation. As the drilling progresses, there are numerous warning signs that critical safety measures have been compromised. These red flags culminate in a catastrophic failure, triggering a series of explosions and fires throughout the rig. The crew must then face a harrowing fight for survival as they attempt to evacuate, contain the impending environmental disaster, and save as many of their colleagues as possible amidst the chaos.