I don't have any hidden microphones in the offices of Universal Studios, but I think it is a fair bet, given Denzel Washingston's credit as Executive Producer of Safe House, that at some point or other someone pitched the film as a cross between Training Day and The Bourne Identity. It shares with the former the basic plot structure of an older, more experienced veteran educating an eager but inexperienced newcomer into the more cynical aspects of their work. It shares with the latter the thematic motif of a talented covert agent gradually becoming aware that the system he works within is littered with corrupt souls who are morally indistinguishable from the terrorists and criminals he is assigned to fight.
Washington plays Tobin Frost, a one-time CIA agent who has gone rogue and is now considered a dangerous threat to national security. As the film opens, he is in South Africa receiving a computer chip with evidence of corruption and illegal activities in each of the world's intelligence agencies. It is indicative of the film's ideology that the MacGuffin chip has evidence not just against one government group that would try to kill him but against everyone. It's not that there are corrupt individuals out to silence Frost, it's that the whole system of espionage is corrupt. One cannot be a spy, the film argues, and not be morally bankrupt. Stay in the business long enough, the villain rationalizes, and you will inevitably have mistakes or "bad calls" that need to be hidden from the public eye by killing those who could hold you accountable.
Frost does not have the chip for too long before he is indeed being shot at (by mercenaries who, in one of the film's several plot holes, are later revealed to be working under the direction of someone who has not yet been informed that Frost has surfaced). After the first of the film's lengthy chase sequences, Frost surrenders himself to the American Consulate as a means of escaping those chasing him. Cut to CIA headquarters where it is determined that the rogue agent should be taken to a safe house—a secret hideout under agency control to be used in emergency situations—where he can be tortured (or "harshly interrogated") for information. Ryan Reynolds plays Matt Weston, whose job it is to maintain the safe house in the middle of nowhere and who is itching to get off the sidelines and into the throes of some real, more exciting, spy work. It is to Weston's safe house that Frost is brought, and it is not too long before Frost's interrogators are dead and Weston is trying to flee the assassins while keeping Frost from getting away.
The core of the film fluctuates between more chases and fights (filmed in the now requisite shaky, hand-held camera style and teal filter coloring) and discussions between Frost and Weston about the meaning of their profession (and whether or not Weston is cut out for it). In the best of these, Frost simultaneously consoles and mocks Weston by telling him that his girlfriend will believe any lie he tells her but that he will eventually leave her anyway because of the inability to have a normal domestic life in the profession he aspires to practice. In this scene and a later exchange between Frost and a forger (who passes for as close to a friend as a man like him can have), we see hints of a better, more thoughtful film—one more interested in genuinely exploring the psychological toll of guilt and disillusionment instead of simply referencing them in quiet interludes to foreshadow (as though foreshadowing were necessary) Weston's inevitable change of heart.