11 unopened birthday cards 18-year-old Preston discovers in his grandmother's closet send him across the Atlantic to London in search of a man he never met: his grandfather. More than anything, he needs to know if his grandfather shares his full moon nights, when thick coarse hair covers his body, when running on all fours feels natural, when the animal inside him emerges. He and his dad shared "this condition." How Preston loved their moonlit nights running through the woods, but since Dad's death, he has been alone and done things he should not, such as rescuing his graduate teaching assistant, Ms. Worth, which got him expelled from his university. Will he find his grandfather? And if he finds him, will his grandfather welcome him after all these years?