The main characters in "A Rip In Heaven" by Jeanine Cummins include Jeanine herself, her brother Tom Cummins, and their cousins, Julie and Robin Kerry. The narrative revolves around the harrowing experience these individuals undergo on the Old Chain of Rocks Bridge in St. Louis, Missouri. Tom Cummins, the sole survivor of the brutal attack, becomes a key character as he grapples with survivor's guilt and the fight for justice. Jeanine Cummins, as the author and family member, provides a deeply emotional and personal perspective on the tragic events and their aftermath.