1) The Bourne Legacy continues the Bourne franchise in a new direction, following a new enhanced CIA agent named Aaron Cross played by Jeremy Renner.
2) The film opens during the events of The Bourne Ultimatum and shows the CIA dealing with Bourne while also trying to cover up the exposed Operation Outcome program which enhanced agents like Cross.
3) Cross teams up with Outcome scientist Marta Shearing, played by Rachel Weisz, as they both need to survive being hunted by the CIA. Their partnership shows potential to be important in future films in the new trilogy.