Frank Moses (Bruce Willis), a former black-ops CIA agent, is now living a quiet life in retirement. However, he begins to feel lonely and often chats on the phone with Sarah (Mary-Louise Parker), a customer service agent working for Frank's pension office in Kansas City.
His life is disrupted when a hit squad raids his house in the middle of the night. Frank kills the assassins and, knowing they would have tapped his phone, goes to Kansas City to protect Sarah. She becomes Frank's reluctant companion while he tries to find out who is trying to kill him, and track down his old black ops team for help. Meanwhile, CIA agent William Cooper (Karl Urban) is assigned to hunt and kill Frank.