Vortex starts where Tempest left off, with Jackson trying to put things right and get on with his life without Holly and Adam. In order to achieve this, he joins the Tempest program, a part of the CIA. I really enjoyed the setting of Jackson being a part of Tempest as it is what made this book exciting. Tempest takes Jackson all over the world in his training and it also introduces some great new characters. Kendrick and Stewart, two female members of Tempest get quite large roles in Vortex and although they're both really different, I loved them both.
With everything that is going on, Jackson himself changes as a character. Unlike the loveable guy we got to know and love in Tempest, he changes quite dramatically at times. With being a part of Tempest and going through a gruelling training scheme, he becomes a bit harder, a bit more guarded and also more determined to make things right. Jackson constantly beats himself up for what happened to Holly before and what he probably could have done to prevent it. Although Jackson does change as a character, I liked this. I think these changes made him a stronger person and also someone who thought things through a bit better.
Unfortunately, when it came to the actual time travel stuff, I just ended up being really confused. Julie Cross uses so much technical terminology and goes into deep and intricate descriptions of how time travel works and I just didn't get it. Even though Jackson attempts to explain this in a simple way early on, it just made my head hurt. There are full jumps, half jumps, jumps that end up in different worlds - basically too much information in a short space of time that doesn't make much sense. I really liked the time travel aspect in the first book, Tempest, but I feel like in this one it was overcomplicated for no reason.
The setting of Vortex provides a hell of a lot of excitement. With a fast pace, Vortex doesn't stop very much for you to catch your breath. There is always something quite big going on and there were plenty of times that I was shocked and just didn't know where the story would go next. There are so many twists and turns in this book and I sometimes didn't know if I was coming or going. However, as this is such a big book, it would have ended up being quite boring without all of these things going on.
Vortex was a really mixed book for me. While I liked the excitement of the story, the time travel aspects were far too confusing.