Harry Bauer was a professional killer. After eight years in the SAS he was the best in the business. That business was Cobra, a shadow agency that took out the trash that was beyond the reach of the law, those guilty of crimes against humanity. Now Harry has resigned. He purpose is to find peace.
But when his former head of operation, Colonel Jane Harris, is gunned down and left fighting for her life under heavy guard at the hospital, Harry know he has one more shipment on trash to take out. His former boss, Brigadier 'Buddy' Byrd tells him to stay out of it - he also tells him their mark had been Russian Mafia selling next generation chemical weapons through Russian contacts at the United Nations.
The Brigadier can't protect him, Cobra cannot protect him. If Harry goes after them he will do so as a rogue killer.
That suits Harry just fine. A rogue killer is exactly what he is.