This is a fairly tepid book, mediocre fare at best, in which the plot revolves around secret, government sanctioned experiments on humans, dealing with some of the ethical themes of today: cloning, genetic engineering of humans, and cross species hybrids.
The story is simple. Two of the test subjects have escaped the confines of the closely guarded, secret laboratory. Matt and Max, a brother and sister team that can fly, are being hunted down. Yet, They need only spread their wings, and, as did Icarus, they can soar up high into the wild blue yonder. The only problem is that hunters must bring them back to the secret lab, before anyone sees them. To further complicate things, Matt and Max do not wish to be caught, because they know that bad things happen in the lab and that people, who are deemed dispensible and no longer necessary, are "put to sleep" and never seen again.
In the outside word, the children separate. Eleven year old Max has the good fortune to run into Frannie O'Neill, a compassionate veterinarian who immediately realizes that there is something extraordinary about Max, beyond the fact that she has real, honest-to-goodness wings and can fly. Frannie is aware that Max is more than the sum of her parts. Together with the help of an FBI agent who calls himself Kit Harrison, they will do everything they can to help Max evade her pursuers, only to become earmarked for death themselves.