"Thirdborn" is a science fiction novel by the author Jessica Khoury. It follows the story of a young girl named Zara, who is born into a society where the firstborn children inherit power and privilege, while the thirdborns are often marginalized. The narrative explores themes of identity, family, and the struggle for acceptance in a rigid social hierarchy. As Zara navigates her world, she discovers her unique abilities and the potential to challenge the status quo. The novel delves into her journey of self-discovery and empowerment, highlighting the importance of resilience and courage in the face of societal expectations.