Everything in Jackson's life is going fine until he and Holly are attacked one morning and Holly is shot. This situation causes Jackson to inadvertently jump back to the year 2007, something he has never done before. When he tries to return, he finds he cannot, and that for some reason unknown to him, he is stuck in the year 2007.
As a result of this plot development, the next part of the novel sees Jackson try again and again to jump back to 2009, in what seems to be a confusing jumble of jumps. This makes the novel somewhat complex because the author has chosen to reveal the plot through the time jumps which means the reader learns along with Jackson. Each jump sends him either to another date in 2007 or to dates further back, such as 2004 when his twin sister Courtney was still alive or to 2003 when he and his sister were followed by CIA agents. But each of these jumps fill Jackson in more on what is really happening in his life, and none of it is what he expects.
"Honestly, most of my actions over the last couple of days had been driven by anything but logic, just a lot of fumbling through time (literally), searching for something concrete to grasp on to. Something real. Facts. Answers. I closed my eyes and focused on the date four years in the past."
Stuck in 2007, Jackson decides to connect with the much younger Holly (whom he hasn't yet met in his original time line) and Adam, hoping that the 2007 version of Adam can help him find a way to return to 2009. Also in the 2007 timeline, Jacksono confronts his father about his role in all of this. Gradually Jackson pieces together what is happening, discovering the truth about his family and his identity, and learning about time travel.
Jackson learns that he is a genetically engineered human who has the "tempest" gene - a gene that gives the ability to time travel. There are plenty of others like him, some of whom are grouped together for evil purposes and who are referred to as the "Enemies of Time". Jackson is capable of making "half-jumps" to other times but these jumps are like branches on a tree - they don't change the current timeline. Only full jumps along a time line do that. To get back to his home base time of 2009, he must make a full jump back, something he hasn't learned how to do at this point.
Eventually though, Jackson does make it back to 2009, where he and his father must face down their adversaries, the Enemies of Time, who see Jackson as a threat to their plans to make the world a very different place. This sets the stage for the climax of the novel. Jackson has to decide whom to believe, and since he has been shown two versions of the future, what he will fight for. He decides that he must work with the CIA to help his father and other agents stop the Enemies of Time before they destroy Earth.
Although Tempest is mainly action driven, there is plenty of romance between Jackson and Holly - perhaps a little too much because it added another layer to the storyline. However it does help to set the stage for the conflict Jackson eventually faces at the end of the novel. Julie Cross develops Jackson from a uncommitted, fun-loving teenager at the beginning of the novel, to a serious, engaged, and intelligent young adult who makes the ultimate sacrifice to save the love of his life, Holly.
Here's the short booktrailer by St. Martin's Press:
Tempest by Julie Cross
St. Martin's Griffin 2011