Lysander Dalton is an agent with the CIA.
He is a reluctant agent, however, having had no desire to get involved but having involvement forced on him. Dalton is an ex-Special Forces officer, risen to the rank of captain in Force Recon, the Marine Corps elite group of the best and fiercest soldiers. The emphasis is on the "ex" as he was dishonorably discharged before arriving at Leavenworth to spend some time for doing the right thing at the wrong time in the military.
While on a mission in the Phillipines helping fight rebels, a Tagalog villager reported that a young girl had been raped by an American and that the man was still terrorizing the village. Investigating, he found the man was one of the sergeants in his company, drunk and belligerent. Seeing what the man had done, Dalton lost it. The sergeant lost an eye and a lung and got many broken bones. Dalton got six months in prison.
As the series starts, Dalton has returned home from prison, home being a very old farm house a mile from the nearest neighbor. He has no great plans for his life except to be left alone and stay out of trouble. He had had enough trouble in the many years in the Marines, seeing action in Panama, the Middle East, Haiti, and, of course at the end, the jungles of the Phillipines.
He is thinking that his life should be peaceful now but someone in Washington has other thoughts and still other people don't agree and Dalton is about to be caught in the middle. Though he wants to be left alone, Dalton finds that old enemies don't forget and some remember hard enough to do something. Luckily, he does't forget his skills.