My mother had wanted a career but had kids instead, a disappointment she coped with by living in bed on a diet of pills. My beloved father, a globetrotting diamond executive, saw only the illusion of normalcy she spun when he was home. Neglected, needy of love, desperate to mask a deep sense of shame, I doubled as an ever-smiling, straight-A, people-pleasing machine. My parents insisted I forfeit my dreams in favor of theirs? Done.

For a quarter-century stretch starting in my twenties, I could only watch as the two went from riches to rags—from an Upper East Side penthouse to a one-bedroom Queens rental—a self-inflicted downfall that defied all reason. Finally, in their old age, when an even worse fate awaited them, chance allowed me to intervene. Though resentful of duty’s call, I was, as ever, a Good Girl.

In the depths of untreated mental illness by then, my mother was a holy terror to all and a specific danger to my father. Having loathed her while hungering for her love, I now loathed her while hungering to take her down. Oh, how I thrilled to the idea of hurting her in order to help her. And oh, how I reveled in her pain.

My zeal at making my mother suffer called both my self-image and my sanity into question, while the immersion in my parents’ lives set me on a path to discovery. Never could I have imagined learning all I did about the father I’d idolized. Or finding compassion for the mother who’d hurt me so.