The world she saved might not be the one she lost. Earth is dying—choked, crowded, and out of time. The only way out is the Bridge: a one-way door to a new beginning, eighty-nine million years in the past. Trauma surgeon Mara Voss wins the lottery. Her daughter Wren wins it with her. Her brother-in-law Ezra—the last family they have—does not. Torn from him at the checkpoint with nothing but a promise, Mara steps through the Bridge into a world untouched by everything that broke the one she left: skies the color they were always meant to be, forests older than imagination, and predators that have never once had to fear a human being. Now she must keep her daughter alive, hold a fractured colony together, and build something worth coming back for—because somewhere behind her, across a hundred million years, someone is still trying to follow. Some promises take longer than a lifetime to keep.