The mysterious murder of a US senator bearing the distinctive trademark of the legendary Soviet assassin \'Cassius\', forces retired CIA operative, Paul Shepherson to team with rookie FBI agent, Ben Geary to solve the crime. Having spent his career chasing Cassius, Shepherdson is convinced his nemesis is long dead, but is pushed to take on the case by his former supervisor, Tom Highland. Geary, who wrote his Master\'s thesis on Shepherdson\'s pursuit of the Soviet killer, is certain that Cassius has resurfaced.
Los Angeles S.W.A.T. officer, Lt. Paul Cutler, is sent to train the Detroit S.W.A.T. team on new anti-terrorism and homeland security techniques. Cutler has a hard time settling into his assignment as he locks horns with his new captain and encounters resistance from the team he must lead. Cutler begins to adjust to his new assignment, starting a budding romance with police psychologist Kim Byers along the way. Unexpectedly, a routine hostage call turns deadly, and a relentless ex-government agent named Walter Hatch vows revenge on Cutler and the entire S.W.A.T. team for killing the woman he loves. Cutler must use his considerable S.W.A.T. training and knowledge to save his teammates and defeat a trained killer.