This is a strong story that portrays healthy, smart girls who stumble upon a time machine key. Together with their dad they must find the machine, figure out the riddle, and collect the pieces that are hidden in different eras of history in order to save the world. A wonderful adventure story, and the author does a great job creating fun and likable characters.
I must say that it's refreshing to find a YA book for girls that ISN'T overwhelmed by a sappy romantic subplot. These girls have goals and dreams, and they are willing to do the work it takes to reach them. They aren't eternally distracted by boys, makeup or clothes, which is nice, and judging from my own girl and her friends, more realistic.
This is a compelling read for girls of all ages, and I can't wait to read Part 2!