Troy Barclay and Amber Neilson are agents with the ATF.
The Alcolhol, Tobacco, and Firearms Bureau, being a national police organization dealing with the legal trafficing in these products, often finds considerable involvement on the international scene, especially with the Mexican border and the drug cartels. For Barclay and Neilson, their activities go far beyond that on a routine basis and they find themselves going up against terrorists, homegrown and imported, intrigue, and even a spot of two seconded to the CIA.
Barclay is described as a tall, lean, dark-haired man with "sturdy build of a long-time weight lifter". If you asked him, he would say his head was odd-shaped, his ears even odder, and the rest of him nothing to talk well of. If you asked the few women he had dated, they would say call him handsome.
Before the ATF he had been an FBI agent for a number of years but was fired for insubordination, a trait that he still holds and practices but either with less a degree or his bosses at the ATF were not so deserving of his biting wit. His professional track record is very good with a considerable number of arrests but the first recorded mission was the biggest thing to happen to him during his 10 years of service.
Things tend to blow up around troy and cars are never safe when he is inside them, especially if he is behind the wheel. The mishaps are usually not his fault but he is undoubtedly a damage magnet. When not on duty, Barclay lives on a small ranch in southern Arizona, a place he loves to get back to.
Neilson is medium height (5'7-5'8"), lean, with dark hair. around 25 yrs old. When she first runs into Barclay he noticed that she tended to dress severely giving her a mannish look but when in civilian attire, she was a knock-out.
In their first case together, she was an agent of the FBI but forced to work as a gofer for a senior agent, the punishment for an incident at the start of her career. Fresh out of the Academy, she had been told to stay with the cars while the other agents conducted a raid. While doing so, she was visited by a large group of gangbangers who tried to vandalize the cars. She put ten of them in the hospital with a lot of broken bones but, a victim of political correctness, she was pulled from street duty and was largely considered a pariah soon to be discharged.
They met when the murder of the First Lady resulted in a task force being created to find the killers. Barclay was the representative from the ATF and Neilson was the "assistant" to the ranking FBI agent. After a cold moment of two when they first met, they quickly learned they worked well together and made an impressive team.
Both are black belts in karate and each is an excellent shot, as would be expected with the ATF but Neilson might be a bit better. They both can more than take care of themselves in combat and each has the scars to prove they would never think of running from an altercation.
As the series progresses, their relationship develops nicely.