From Mickey Fisher, the creator of “Extant,” this grounded new thriller follows Mara Kint (Sarah Shahi), a former hostage negotiator and expert on human behavior who became a college professor after facing an unimaginable personal tragedy. But when her former boss, Charlie Ventana (Dennis Haysbert), brings her in to save ordinary people who have lost themselves in a highly advanced immersive virtual-reality program in which you can live out your wildest dreams, she finds that in saving others, she may actually have discovered a way to save herself.