The #1 New York Times bestselling author Marieke Nijkamp and artist Manuel Preitano unveil a graphic novel that explores the dark corridors of Barbara Gordon's first mystery: herself. After a gunshot leaves her paralyzed below the waist, Barbara Gordon must undergo physical and mental rehabilitation at Arkham Center for Independence. She must adapt to a new normal, but she cannot shake the feeling that something is dangerously amiss. Strange sounds escape at night while patients start to go missing. Is this suspicion simply a result of her trauma? Or does Barbara actually hear voices coming from the center's labyrinthine hallways? It's up to Barbara to put the pieces together to solve the mysteries behind the walls. In The Oracle Code, universal truths cannot be escaped, and Barbara Gordon must battle the phantoms of her past before they consume her future.