High school sophomore, Alex Grabovski, is cursed with a gift: the ability to see the goodness and evil in her fellow human beings in the form of halos-rings of light or darkness-that surround the body. Her goals in life are to keep moving, find her best friend, and to remain invisible. A new foster family and new school offer her a real chance at a normal life. But in order to stay, she must accept that her gift, The Gift of the Saints, has been bestowed for a purpose and confront the overwhelming darkness she fears.

Then he appears.

Gabriel is a Seraph, a guardian angel sent in the mortal body of a sixteen-year-old boy to protect Alex at the time in her life when she needs it most. Although he is as old as time, Gabriel's teenage form reacts to Alex in an unexpected, unprecedented way. He falls hopelessly in love with her.

When their school erupts in violence, Gabriel and Alex realize why the guardian has been sent. But can they rise above human emotions to fulfill their destinies, even if it means the outcome will rip their fragile world apart?