Rose and Lily Winters are twins, as close as the bond implies; they feel each other’s emotions, taste what the other is feeling. Like most young women, they’ve struggled with their bodies and food since childhood, and high school finds them turning to food—or not—to battle the waves of insecurity and the yearning for popularity. But their connection can be as destructive as it is supportive, a yin to yang. Within a few years, Rose is about to mark her one-year anniversary in a rehabilitation facility for anorexics. Lily, her sole visitor, is the only thing tethering her to a normal life. But Lily’s own struggles, while less apparent than her sister’s, are equally profound. When Lily joins an extreme cult diet group—led by a social media faux-feminist—and begins to lose weight at an alarming rate, Rose determines to become well enough to leave the facility to save her. And perhaps save herself.