Evie Evans is an agent with Counter Intelligence.
It is not quite stated if CI, as it is repeatedly referred, is a part of the military or one of the government's alphabet soup intelligence agency but the latter is more likely. It is responsible for tracking down those people who would spy on us and from the sounds of things it quite often plays a lot rougher than it probably would like known. Leading the organization is a man with the title of Commander.
Evans is an agent through most of the series but she was not when the first recorded adventure happens. She was then a former agent having given up her career over a decade before. Life, though, and very cruel Fates, brought her back.
After graduating from high school, Evans chose to enter the military and served with distinction for four years. Then she moved to CI and became an agent, all to the unhappiness of the Commander at the time, a man who happened to be her father. He might have had great love for his offspring but that did not extend to giving her easy assignments. She did not back down no matter what the challenge.
What finally got her to quit was a pregnancy. Jack, her fellow agent and ofttimes lover, and she had a baby. It was not planned by any means but they both decided for the sake of the child, they would get married and together they would raise him. Jack chose to stay an agent and that meant he was gone for long periods of time but when he was at home they were a family and that family increased a couple years later and now Evans was the proud mother of two and an active member of the PTA.
She would come to realize that her husband Jack was active with the PTA as well but not like she. He tended to spend time with the other moms. And apparently with any other female who got within reach. The marriage moved to rocky grounds but for the sake of the children, she hung in there.
Then Jack is reported dead. Then maybe he isn't. Then people who were very unhappy with whatever Jack was doing on the side (not counting the PTA) were even angrier that he was dead and maybe he had left something important at home and Evans is told in no uncertain terms she had best hand it (whatever it was) over or she and her children would die.
Evans is not a trained assassin. She is not even an in-shape ready for action operative. She is a homemaker whose home has been thoroughly disrupted and her children threatened and she tired and scared and angry at all get and that is when things start happening.