Two miles into the earth, nine Appalachian miners struggle to survive after a methane explosion leaves them with one hour of oxygen.

After a tense few months following a miscarriage and an unemployment spell, things are finally looking up for Sean (Kevin Sizemore) and Lisa Miller (Elizabeth Harnois) when Sean lands his dream job at an advertising firm. But when Sean’s assistant, Jen (Cerina Vincent), his self-proclaimed “Work Wife,” begins vying for his affection, it soon becomes clear that she will stop at nothing to rip their marriage apart and claim him as her own.