Jackson Stone is an agent with Scorpion.
That is a small group of trained operatives put out into the field by Polaris.
Polaris is an agency employing "hundreds" of people, many in a headquarters equipped with "enough weapons to overthrow a small city". We are told early on that it "did its work behind the scenes". We are also informed that it was "one of the most secretive and ruthless spy agencies in the world" and that it operated "free from national and international law, they took to the shadows, securing ancient artifacts, chasing UFOs, and documenting the paranormal. Their agents came from all walks of life, and their reach extended into every nation's intelligence apparatus."
Such a powerful organization needs a powerful enemy to keep it on its toes and Polaris has that in Eclipse, "an organization whose power crept into every institution." Need an election rigged or a politician or CEO removed or even a government toppled, Eclipse was the one to call.
To be the main fighting force to take on its opponents, like Eclipse, Scorpion has a highly trained cadre of elite operatives called Scorpion. Most of these highly deadly people came from special forces groups around the world but some, like Stone, come from different backgrounds, bringing special skillsets to the team.
Stone, when we first meet him, is an analyst studying, among other things, whether "ancient artifacts have unknown powers". So far the answer is 'no', but he "was there to make sure". Stone is very comfortable in his own world, seated at his desk in his small, compact office surrounded by three monitors and a keyboard, as well as a baseball and bat signed by Jackie Robinson. He is summoned to the offices of Polaris Director Hill to be told he was heading out into the field for the first time, something which makes Stone cautious and nervous but also excited. Stone was not a complete novice, of course, having "spent months training with firearms, martial arts and the art of deception" but this would be his first foray into actual action. Oddly, this 'promotion' comes right after Stone is asked about his recovery from his recent heart transplant!
Out in the field Stone would be working with, among others, Dr. Alabama Wren, a gorgeous red-haired woman who was as deadly as she was paranoid, though she preferred the term "prepared". "With cameras and sensors and alarms and her two Dobermans, she felt secure. At least, as secure as she could be in the civilian world. She left nothing to chance and bought her food over the web and never from the same place."
Though the series was named for Stone, it would not have been surprising to see Wren get equal billing, if not the top spot herself. She is a trained and experienced operative when we first meet, ready to take part with any mission, "from wet work to robbery". Besides being extremely qualified in such matters, Wren has one other gift that makes her very valuable: she is an empath. While she cannot "read minds, no one could", her skills at reading people and correctly gauging their inner thoughts and fears bordered on just plain spooky. No wonder Polaris valued her so highly.
- Said by Polaris' Director to a hesitant Jackson Stone about becoming an agent: "Only fools think they're ready to be a field agent."