Most 16-year-olds cause at least some damage on their path to adulthood. But Saira Sehgal has vowed to first do no harm. A girl genius, she’s the youngest MD in America—and she hasn’t picked an easy specialty: She’s working on the cancer ward.

Saira’s always been good at getting what she wants, but she’s new to adult challenges—like getting out from under the thumb of her doting mother, who works at the same hospital; like proving herself to coworkers who don’t take her seriously; and crushing on a cute boy who happens to have stage-two leukemia.

Turns out “heartbreak” is one ailment Saira still doesn’t know how to treat.