Myra Walker was the wife of former Secretary of War Henry Walker. She and her husband decided to leave the United States from under the authority of the Noah Grace Administration and escape with a valuable recording of Grace's conspiracy concerning Project Omega. The couple headed towards Chimera-occupied Chicago in the hopes of reaching the underground resistance movement, Freedom First, and broadcasting the secret of Project Omega to the public. However, Myra and Henry Walker were captured by a Chimera patrol near Madison, Wisconsin and imprisoned in a foundry pit, where Myra worked as a nurse.
When her husband, Henry, got into a fight with another unruly prisoner named Marcus Tolly, Tolly retaliated by telling Norma Collins, a quisling to the Chimera, into choosing Myra along with the rest of the doctors into the foundry's makeshift Conversion Center. In the Center Myra was converted by a Spinner and into a Grim.