Jack McClure is an agent with the ATF.
More importantly to the series, McClure is a friend to the President of the United States and it is this friendship that moves the highly impressive Special Agent into cases he normally would have never seen.
McClure has a rough upbringing. Suffering from dyslexia that made him a bad student in school, laughed at and taunted by classmates, and yelled at and abused at home, he never fit in. It would be many hard years before he began to realize that the dyslexia allowed him to look at things in ways that those without the affliction would never consider and he started to use it. He became a government agent, met and fell in love with Sharon, married and became a father. His daughter, Emma, was the high point in his life.
As the series opens, McClure is struggling with a shattered life. His daughter, grown to adulthood and attending college, had been killed many months before in a car crash and, throwing himself into his work to focus on something other than the pain, he never saw his marriage disintegrate. Alone and extremely unhappy, he is barely hanging on.
When Emma's best friend, Ally, is kidnapped, her rescue becomes a chance for McClure to get some purpose back in his life. He does not realize that while trying to save this college-age daughter of the newly elected President, he will have to face the ghost of his daughter and the tragedy of her end. This decision to help find her will mark the beginning for a different phase of his life. Still an ATF officer, he is moved from law enforcement to the shadowy world of underhanded politics, international backstabbing, and the strange marriage of conveniences that bring those out for money to work with those out for power.
Of note in this series is how the daughter of the President, Ally Carson, rises in importance in the series from being a kidnap victim to being a person working side-by-side with McClure. In the third book, the tag "A McClure - Carson Novel" can be found.