The Search for Acceptance and Connection

Cinder has the misfortune of living with an adoptive family that neither loves nor appreciates her. The income she brings in from her work as a mechanic goes toward supporting her family, but she is still treated as a burden by her cruel stepmother, Adri. Like Adri, Cinder's stepsister Pearl despises Cinder—in large part due to the fact that Cinder is a cyborg. The only member of Cinder's immediate family that shows her any kindness is Peony, Cinder's other stepsister and only real human friend. When Peony contracts the fatal disease letumosis, Cinder is devastated and further alienated from Adri and Pearl, who blame her for Peony's demise.

Beyond her immediate family, Cinder knows little about where she came from or who her birth parents are, which contributes to her feelings of loneliness. To Cinder's knowledge, her parents (whom she cannot remember) died in the same hover crash that severely injured her as a child. As a result of the stigma surrounding cyborgs, Cinder lives an isolated existence and is reluctant to get too close to others for fear that they will discover what she is—in particular, she worries that Prince Kai will shun her if he learns that she is a cyborg. Aside from Peony, Cinder's only real relationship is not with a human at all, but with an android named Iko. Cinder's story culminates in the discovery of her true origins: she is the lost Princess Selene of Luna and the heir to the Lunar throne. Cinder quickly learns, however, that even with her true identity revealed, she will never find the acceptance she is looking for in others if she does not first learn to accept herself.

Bravery Against All Odds

As Cinder learns more about herself, Kai, and Levana's plans for Earth, she feels a great deal of responsibility to protect her country and the people of Earth—despite the discrimination she has faced at their hands. She feels this sense of responsibility so strongly that she is even willing to put her own life at risk, which is precisely what she does when she chooses to warn Kai about Levana's plot rather than escape New Beijing as she had planned. At the ball, Cinder desperately tries to prevent Kai from agreeing to marry Levana, who intends to kill Kai as soon as he is no longer of use to her. When Kai refuses to save himself, Cinder makes a public scene, risking everything to try and prevent his alliance with Levana. In doing so, she is publicly exposed as not only a cyborg, but also a Lunar.

At the novel's conclusion, Cinder finds herself in prison, having been arrested at the ball on Levana's orders and seemingly abandoned by Kai. Though Cinder has grown up being treated as a servant and a second-class citizen, she still finds the courage to stand up for herself and those she cares about. In doing so, Cinder demonstrates the importance of inner strength even (and perhaps especially) in the absence of social or political power. Though her decisions have cost her dearly, Cinder does not succumb to feelings of helplessness; instead, she is more determined than ever to survive and right the injustices she has witnessed.

Personal Sacrifice

Cinder and Kai's choices throughout the novel repeatedly demonstrate the necessity and terrible burden of personal sacrifice. We learn early on that despite the cruel treatment she has faced as a cyborg, Cinder is a compassionate person, especially toward the few individuals with whom she has managed to form a close relationship. When her adopted sister Peony is diagnosed with letumosis, Cinder agrees to act as a test subject for Dr. Erland's research to procure a potential cure for Peony. After befriending and falling for Kai, Cinder puts her own personal safety and reputation at risk when she attends the ball to warn him about Levana's plans. Even though she knows being exposed as a cyborg or a Lunar might mean losing Kai's admiration and friendship, Cinder is resolved to save him and the country from Levana—no matter the personal cost.

Kai, too, proves willing to sacrifice his own happiness for the good of his people. Though his father's untimely death forces him to assume the throne at a young age, Kai is keenly aware of his duty and never shirks his enormous responsibilities as the ruler of a country ravaged by disease and under threat from the Lunars. Cinder manages to warn Kai that Levana plans to kill him after marrying him. Kai, however, is determined to move forward with the marriage anyway, knowing that it may be the only way to save his people from the deadly letumosis.