Aydan Kelly is an agent with INSET.
Well, probably, although that might not be the whole truth. INSET is the Integrated National Security Teams, a section of the Canadian intelligence community made up of task forces from various other groups to coordinate processing of data and taking action when required. It is for them that she will come to work but her handler, a Royal Canadian Mounted Police officer named John Kane, really works for a general in the armed forces so who calls the shots is not quite stated.
As the series begins she is not an agent, would never think of becoming one, and likely did not even know what INSET was. Another way of putting it, "despite her penchant for weapons and ripe language, Aydan Kelly’s resume reads 'bookkeeper', not 'bad-ass'". She has been a office rat for most of her adult life, a life that has her now well into her 40's but still definitely, decidedly not dead. Perhaps mid-life crisis has set in or perhaps she just got tired of what was a very hectic city life but a change was needed. As the series starts, she has left the big city "to fulfill her dream of rural tranquility". Her husband, of whom she has many good memories, died some time back.
The new start she was seeking definitely came but it was not a life she expected. On a trip back to the city and her old house to meet a possible buyer, she gets carjacked by someone she is later told doesn't exist. He certainly existed when he accosted Kelly and she had the bruises and the shakey hands to prove it.
That is when she meets Kane. He came to her rescue and saved her, although she had been doing a fair job of handling the situation already. Nevertheless, he put an end to the problem, and the would-be kidnapper. Then he set about arresting her. Granted, she did accost him not knowing he was one of the good guys and she had been "with" the man he was after and had no good explanation for the latter.
Still, being grabbed, shot at, and then arrested should have been enough for anyone but it would be just the beginning to a new life and a new career, albeit mostly unofficially the latter. To the outside world she remained a bookkeeper living in the countryside taking on clients when she wants. To the fellow members of her group, she is an operative, a sometimes foul-mouthed, opinionated one but a woman capable of swinging a mean crowbar when she has to.
For the record, Kelly is 46 years old, 5'10" tall, weighs 160 lbs, and is in pretty good shape except for the "extra ten pounds or so around the middle". She is by no means an exhibitionist but if someone, especially someone as incredibly sexy and handsome as her oft-times partner, Kane, saw her naked (which he has), she would hardly shrink away with embarrassment. She enjoys beautiful red hair, never a bad thing for a good looking woman, and while she often refers to herself as an old woman, she knows she really isn't and so do the men she meets, at least the smart ones.