These beings have attempted to find a key, that will allow them to control other beings and go into the world and make slaves of others. Gideon was training to be a part of the Army RASP, when during a training exercise, his chute failed. When this happened he hit the ground and died, but the other members of the RASP worked on him to bring him back. He went to the hospital and was sent home with many broken bones. He got better faster and was then found by Daryn, who is a Seeker. Together they gather the other riders of the Four Horsemen and together they gather to become a group.
The story was fascinating and looked at how they come together and how they trained and helped each other and grew and learned about themselves and each other.
I started the book one night, staying up until after midnight reading it (only about 2 hours) and it is a library book, my daughters brought home for their book club. Every now and then they get a book that when they discuss, I feel like reading and seeing what the story is about. So this led to my only reading when I could get my hands on a copy of the book (theirs).