Identical twins Kate and Violet have always been different--able to sense other people's secrets and know about future events. As they grew up, Vi embraced her gift and pursued a career as a pyschic medium, while Kate denied it and settled down with a family. An earthquake in their hometown of Saint Louis and Vi's vision of a more devastating quake to come, however, force Kate to reconcile the strained relationship with her twin and come to grips with the truth about herself.