Thea has never seen the sun. Her extraordinary people, suspected of witchcraft and nearly driven to extinction, have retreated to a secret world they've built deep inside the arctic ice. As Thea dreams of a path to the earth's surface, Peter's search for answers brings him ever closer to her hidden home.
I read When You Reach Me first. First Light has the same element of science mixed in with a realistic setting, a really nice read.
The story was very well-plotted, though I couldn't help liking Thea's world, Gracehope, a little better. It has a very interesting matriarchy that I think is really creative. A lot of symbolism is involved, as well as some intricate more fantasy elements.
The bonds of friendship across such impossible boundaries were very powerful. The alien aspects of each new world were extremely well-written, and the way the characters adjusted together in each new situation was very heartwarming. Overall, I liked When You Reach Me better, but this is definitely worth reading for anyone who's looking for something decidedly new. :D