Simultaneous

When federal agent Grant Lukather investigates what appears to be routine terrorist chatter through his department's predictive analytics system, he stumbles into a case that challenges everything he understands about reality. His investigation leads him to therapist Sarah Newcomb, whose unconventional past-life regression work has uncovered something far more disturbing than repressed memories. Together with one of Sarah's patients, they find themselves tracking a threat that operates across multiple timelines and states of consciousness, forcing them into a deadly race where the rules of cause and effect no longer apply.

The multi-narrator approach proves essential to this complex thriller, with Marin Ireland, Ray Porter, and Stephanie Sheh each bringing distinct vocal personalities that help listeners navigate the story's intricate timeline shifts and consciousness transfers. Ireland captures Sarah's professional skepticism giving way to terrified certainty, while Porter grounds Grant's federal agent pragmatism against increasingly impossible circumstances. Sheh's performance adds crucial emotional depth to the patient character whose experiences unlock the mystery's horrifying scope. The audio format enhances Heisserer's mind-bending narrative structure, allowing the vocal performances to guide listeners through reality's fractures with clarity and mounting suspense.