Stella is the protagonist of the novel as well as the first-person narrator. Her defining trait is her loyalty. This loyalty hinders her at times, but it allows her to heal. She is traumatized at the beginning of the novel due to an airport explosion that took the life of her handler, Connie. She is unable to bond with new handlers because she thinks Connie is still alive and wants to go back to her. Esperanza helps Stella understand that Connie is dead. Stella does not bond instantly with Cloe after that, but she does open herself up to the girl. The two grow to love each other, and Stella’s fierce loyalty to Cloe is what enables her to overcome her fear and regain confidence in herself.

At the beginning of the novel, Stella sees her self-worth in black-and-white terms, something she needs to change in order to grow and heal. When Connie was alive, she repeatedly told Stella that she was a good dog, and this became part of Stella’s idea of herself. When Stella realizes Connie has died, she begins to think that she is a bad dog because she failed to protect Connie. At her darkest hour, however, Connie returns to remind her that she can make mistakes and still be a good dog.