Rising seas are only the beginning of Imogen Holloway’s problems. Her Cambridge home is at risk of sinking beneath the waters, her job with the Climate Cartography Corps hangs in the balance, and her relationship with Alix—her brilliant nonbinary teen obsessed with photographing climate refugees—feels one argument away from collapse. After Alix is arrested for a curfew violation, Imogen is stunned to discover the ringleaders were her own parents, Elara and Lucas.

But before she can confront them, they vanish—leaving behind a hand-drawn map, a photograph of a tornado memorial, a list of missing children, and a decades-old article about an ecoterrorist attack that ignited the Water Wars in the Colorado River Basin.

When the privatized security forces known as the Firms arrest Elara and Lucas for kidnapping an orphan in the no-man’s-land between Kansas and Colorado, Imogen and Alix set out on a perilous cross-country search for answers. Why were her parents so interested in this boy, and what is his connection to the Firms? As the trail draws them into her parents’ shadowy past, Imogen must decide how much she’s willing to sacrifice—for truth, for family, and for her fragile bond with Alix—and she’s forced to wonder: Does she really known her family at all?

In a world remade by climate collapse and surveillance-state overreach, The Hidden Heart explores how families are shaped—and sometimes shattered—by forces far beyond their control.