Lee Chandler is a brooding, irritable loner who works as a handyman for a Boston apartment block. One damp winter day he gets a call summoning him to his hometown, north of the city. His brother's heart has given out suddenly, and he's been named guardian to his 16-year-old nephew. As if losing his only sibling and doubts about raising a teenager weren't enough, his return to the past re-opens an unspeakable tragedy.

In April 2010, there is no oil exploration operation in the Gulf of Mexico to compare with the Deepwater Horizon oil rig with its size or sheer depth of its drilling. However, the project for the BP oil company is beset with technical difficulties to the point where the general operational supervisor, Jimmy Harrell, and his Chief Electrical Engineer, Mike Williams, are concerned potentially dangerous trouble is brewing. Unfortunately, visiting BP executives, frustrated by the project's long delays, order curtailed site inspections and slanted system tests to make up for lost time even as Harrell, Williams and his team helplessly protest for the sake of proper safety. On April 20, the workers' fears are realized in the worst possible way when the rig's various structural and system flaws spark a catastrophic cascade of failures that would create a massive blowout and explosion that threatens them all, even as it also begins the worst environmental disaster in US history.