Maya Shulman and Alex Rubin met in 1992, when she was a Ukrainian exchange student with "a devil in her head" about becoming a chef instead of a medical worker, and he was the coddled son of Russian immigrants wanting a less predictable life.

Twenty years later, Maya Rubin is a medical worker in suburban New Jersey, and Alex is his father's second in the family business. The great dislocation of their lives is their eight-year-old son, Max--adopted from two teenagers in Montana despite Alex's view that "adopted children are second-class."

At once a salvation and a mystery to his parents--with whom Max's biological mother left him with the cryptic exhortation, "Don't let my baby do rodeo"--Max suddenly turns feral, consorting with wild animals, eating grass, and running away to sit facedown in a river.

Searching for answers, Maya convinces Alex to embark on a cross-country trip to Montana to track down Max's birth parents. But it's Maya who's illuminated by the journey, her own erstwhile wildness summoned for a reckoning by the unsparing landscape, with seismic consequences for herself and her family.