This was a fun young adult/teen adventure. I realize that the characters are not teens, but I felt that was how they were portrayed and developed. Less testoterone and invective laden back-and-forth may have brought the maturity level of the characters up a bit closer to their actual ages. Of course, I'm an older reader and may just not have appreciated this dialogue as much as a younger reader might.
On to the story, the pace held my attention and the plot came together pretty well, although a bit choppily (is that a word?). There was not enough back story in order to clearly understand how the characters ended up in their precarious position in the first place. More about the original time travel event would have been very helpful-althoug it may come about in the subsequent parts, which I have yet to read.
Overall, I found it a fun read and feel like Mr. Rock probably enjoyed writing it a great deal. I also feel like he has the ability to tie it together in the future parts as the pieces are all there.