As a child, Annie Baskin envied her older sister. Sarah was beautiful, smart, popular, and contemptuous of her messy, graceless kid sister. Annie grew up in Sarah's shadow, knowing she was second-tier, second-rate, an also-ran. The other Baskin girl.

Now an adult, Sarah lives a life of perfection: perfect husband, perfect children, perfect home. Annie has made peace with her own far less elegant life. But when a crisis shatters Sarah's world, she turns to the one person she can rely on: her sister Annie.

While Annie performs favor after favor for her sister, she becomes deeply embedded in Sarah's exquisite world. All this could be hers, she realizes—if she can believe she's worthy of it. If she can convince herself she wants it. If she can figure out who she is, where she belongs, and what she's capable of.

Laughter and tears. Fury and compassion. Resentment and love. As Annie learns, sisterhood is all those things, and more.