This is a YA book, and I really enjoyed it. I've really gotten into the historical fiction lately, especially the YA stuff.
This is set in 1943, during World War II. One of our main characters is Dewey Kerrigan. Her father is a scientist and they live in a town that doesn't officially exist, Los Alamos, New Mexico. The scientists here are working on a very secret military project called only "the gadget" that is supposed to be able to end the war if they can just get it right. Dewey is kind of a tomboy in that she enjoys building mechanical type projects. Another girl living in this nonexistent town is Suze Gordon. Suze is also kind of an outsider with the other girls, but tries her hardest at first to fit in with the girls in the town. Due to Dewey's father being called to Washington to help with the project politically, Dewey ends up staying with Suze and her family. A friendship forms after they come to see what they have in common.
Of course the gadget does get invented, and there is a tragedy for Dewey. I was glad to see that there is a sequel, another book I had noticed before I even read this one, called White Sands, Red Menace. I have it to read, so it will probably be one of my next YA books. Or I'll read it after the Lincoln Child book I'm reading now.