Footprints in the snow

Evie's life couldn't have been better. She had her dream family. She was a stay-at-home mom, her husband, Marco, was the head nurse at a hospital, and she had twins, Josh and Julie. Everything seems perfect, until a snowstorm hits. Evie and Marco wake to find Josh and Julie missing from their beds. The police only find one bone-chilling clue. A set of footprints in their backyard, leading from their back door, to the icy road.