"What Light" is a young adult novel by Jay Asher that tells the story of Sierra, a girl who spends her Christmas tree lot in Oregon each holiday season. She navigates the challenges of teenage life, including friendships, family dynamics, and the complexities of first love. The plot thickens when Sierra meets Cal, a boy with a troubled past. As they grow closer, Sierra must decide whether to trust him and confront the secrets that could affect their relationship. The story explores themes of love, forgiveness, and the importance of understanding others.