When the assassination of a U.S. senator bears the signature style of a Russian spy known as Cassius, CIA director Tom Highland (Martin Sheen) calls top operative Paul Shepherdson (Richard Gere) out of retirement to investigate. Paul's partner on the case is Ben Geary (Topher Grace), a young agent who also has studied Cassius and is certain the Russian is behind the slaying, even though Paul insists that Cassius is long dead. But, Paul may not be who he claims to be.