Country music superstar Faith Hill is devastated by a secret tragedy -- her newborn daughter is fighting for life.

While Faith and hubby Tim McGraw announced to the world that they'd been blessed with a "beautiful healthy baby girl," in reality they were mounting a heartbreaking round-the-clock vigil at a Nashville hospital.

The issue that is on sale now reveals what's wrong with the infant, the life-and-death drama in the neonatal intensive care unit, Faith and Tim's anguish ... and more.