Two years ago, Bea’s life was upended when her beloved twin sister, Audrey, died. Audrey was captivating, an extrovert, their mother’s golden child. Bea was “different,” too intense, and chronically lonely.

Now, in her late twenties, having taken time away to grieve, Bea is back home in Park Slope, Brooklyn, her spirits finally buoyed by her plan to start a dog kennel. Inspired by the childhood dream she once shared with Audrey and old, now-estranged friends Tatum and Layla, she’s sure this will be the perfect ode to her sister’s life. Despite what people say, Bea knows she took good care of Audrey in the months before her death, and hopes to do the same for needy dogs. But she’ll have to ask for help.

Tatum is dissatisfied with her assistant-level publishing job and icked by her live-in college boyfriend. Layla, on the other hand, has a full-time assistant but no job, thanks to her mother’s immense fortune. Both are desperate for purpose and well-primed for Bea’s unexpected business proposition.

But as they reintegrate into one another’s lives, simmering tensions—and attractions—emerge, and a sinister darkness breaks through to the surface. What do they really want from one another? What happens when buried secrets come to light? And when is the right time to abandon an outdated dream—or a lifelong friendship?

Chilling, twisty, and surprisingly tender, Harmless explores the confusion and messiness of growing up—and asks if we can ever really outrun what haunts us most.