After being diagnosed in her early 40s with metastatic melanoma -- a "rapidly fatal" form of cancer -- journalist and mother of two Mary Elizabeth Williams finds herself in a race against the clock. She takes a once-in-a-lifetime chance and joins a clinical trial for immunotherapy, a revolutionary drug regimen that trains the body to vanquish malignant cells. Astonishingly, her cancer disappears entirely in just a few weeks. But at the same time, her best friend embarks on a cancer journey of her own -- with very different results. Williams's experiences as a patient and a medical test subject reveal with stark honesty what it takes to weather disease, the extraordinary new developments that are rewriting the rules of science --and the healing power of human connection.