As small children, Francine and her twin Philip shared a seemingly unbreakable bond--but in adolescence the connection frayed, and in adulthood the siblings are locked in a repeating loop of complex, destructive emotions. Matters have reached a breaking point, and Francine, now in her thirties and the married mother of two small boys, is convinced that Philip's teenaged infatuation with religion and subsequent, ongoing obsession with his sister's "moral impropriety"--sparked by his discovery of her involvement in a forbidden relationship--are to blame. As storm clouds of resentment and mutual betrayal gather ominously, threatening to upend both siblings' lives and damage their families, Francine unexpectedly finds herself in a situation that mirrors her earlier transgression: stirred and unsettled by her attraction to a wildly inappropriate man. And the one person who suspects is the last person she trusts--her disapproving twin.