The Metal Gear Solid series is notorious for its dense storylines, filled with plot twists and schemes-within-schemes. Even if you've played all the games, it can be hard to keep the plot straight in your head.
Before you play Metal Gear Solid 5: The Phantom Pain, refresh your memory of the story to date with a brief run-down of the events from the games that lead up to it.
Big BossBig Boss (aka Naked Snake, Venom Snake, Punished Snake) was once a decorated covert operative for the United States during the Cold War. However, his commitment to his country is shaken by the events of Metal Gear Solid 3 in 1964. He was sent to stop a Soviet splinter group from attacking the United States with an experimental superweapon. To complete his mission he was forced to kill his mentor Boss, who had apparently joined the terrorists.
As it turns out, though, the mission had a secret objective: the United States wanted to secure the Philosopher's Legacy, a vast fortune acquired by the rogue Soviet group. Boss had willingly acted as a traitor to help the U.S. secure the fortune and then let her protege kill her to keep this secret.
Big Boss' disillusionment over being used as a pawn by his government eventually leads him to go rogue. In 1970, he's invited to join a new organization called The Patriots by his former CIA commander Zero and covert agent Ocelot. This group's goal was to fulfill Boss' goal of a unified world. However, Big Boss leaves after a dispute with Zero over the group's direction.
By the events of Metal Gear Solid: Peace Walker in 1974, Big Boss is now leading his own mercenary army called Militaires Sans Frontieres (MSF). He has a very idealistic objective for the group: providing aid to countries or individuals in need of help regardless of politics. He essentially wants soldiers to be able to make their own decisions instead of being driven by politicians. While MSF grows into a powerful force, its success doesn't last (more on that later).