Blue Sargent has found things. For the first time in her life, she has friends she can trust, a group to which she can belong. The Raven Boys have taken her in as one of their own. Their problems have become hers, and her problems have become theirs. The trick with found things, though, is how easily they can be lost. Friends can betray. Mothers can disappear. Visions can mislead. Certainties can unravel.

In all the years she has watched the wolves in the woods behind her house, Grace has been particularly drawn to an unusual yellow-eyed wolf, unaware he turns into a human for a short time each year, but when the two find one another in human form, they vow to do whatever it takes to stay together.