Susie and Allison were best friends. They planned to grow old together—two grumpy old ladies on a crooked front porch—but fate had other plans. Allison fell ill with cancer. Although they both knew the prognosis was not good, they pressed forward with treatments and hope. Hope sustained them for a while, but the treatments didn't work. Susie was forced to watch her best friend sicken, suffer, and ultimately, die.

After losing Allison, Susie feels as though she's losing her mind. They call it a nervous breakdown, and Susie is happy to believe the doctors and move on—except something has changed. Somehow, Susie can hear and communicate with Allison. She suspects she really might have gone mad, but soon the two friends realize they've bridged a miraculous gap between the living and the dead.

Together, they travel through the afterlife on either side of the divide. Through Allison's observations, the two brave friends are able to seek out the meaning of their lives, solve the mystery of death, and forge a friendship that will last until eternity. Cancer took Allison away; hope returned her to Susie. Their voyage is one of wonder and self-discovery—but most of all, it is a story of devoted and never-ending love.