In "Lock and Key", Sarah Dessen invites us into the tumultuous life of Ruby Cooper, a high school senior who has become accustomed to fending for herself. After her mother's sudden disappearance, Ruby's estranged sister, Cora, takes her into a world of relative luxury. Despite the warmth of Cora's upscale home and the charm of her neighbor Nate, Ruby clings to her independence, distrusting the sudden bounty of good fortune. As Ruby navigates a maze of new experiences, a private school education, and the complexities of family bonds she previously wrote off, she is challenged to redefine her understanding of trust, family, and the possibility of love.