Ted Oliver is an agent with the CIA.
He represents a refreshing style of operative from the kind usually seen. There are numerous operatives who are rebels, who angered their superiors but, because they get the job done, are tolerated and even begrudgingly respected. Oliver is not one of those. He usually gets the job done but when he messes up, as he has before the start of the series, he is demoted and almost sacked.
When we first meet Oliver, he is teaching a course at the Academy, put there because the senior officials do not know what to do with him after a messy ending to a previous assignment. He had not done anything wrong or illegal; the mission just did not end nicely. Reluctant to put him back in the field, they decide to make him an instructor. While his actual transgressions are kept quiet, the fact that they exist is not a secret and all his students know he was being "punished" and they want to know why.
Redemption, of a sort, comes soon when a case with his name on it, literally, comes along and Oliver is 'allowed' back in action, this time in Mexico where he will shortly become the ranking case officer. No one really expects Oliver to not mess it up. But it is Mexico so 'what is the worst that can happen?'
The Agency seems to have forgotten that Mexico is our neighbor. And Oliver is not a screw-up, the previous mission notwithstanding. He is a darn good operative when the chips are down and, unfortunately for Oliver, they seem to be down a great deal.