UnDead Girl by Stephen Simpson is a young adult fiction novel that introduces Genesis, a teenager who discovers she is an engineered undead predator created in a laboratory to survive a pending zombie apocalypse.

After her body biologically shuts down, she is taken to a secret facility where she meets nine other youths, including the enigmatic Eli and the hostile Amelia, who were all designed to retain their human intelligence despite being technically dead.

Under the guidance of scientists like her adoptive father, Peter Mathison, the group undergoes rigorous combat training with melee weapons and archery to serve as a protective buffer for humanity.

The narrative highlights the emotional trauma of their transformation, specifically when a peer named Cornelius fails to stabilise and must be destroyed.

As Genesis grapples with her new identity and burgeoning feelings for Eli, she learns that a global viral outbreak has already begun to collapse civilisation.