In The Mason Gambit, after five years in the Afghan desert, Captain Mason has received tragic news and must return to his family. There are two issues: first, he's been missing for three years and was presumed dead; second, a strange virus has struck the city, with the potential to wipe out the entire population. For the time being, he'll have to work with a mysterious covert international organization to figure out what's going on here. Nothing on the battlefield could've ever prepared Captain Mason for what he's about to encounter throughout this game.