She was born in the wreckage of her parents' car after it had crashed on the way to a hospital, killing Magnús and traumatizing Riley. The crash was caused by poor visibility during a snowstorm. After giving birth, Riley left the car and tried to carry Lúna to safety, but she collapsed from exhaustion and Lúna died in her arms. Yrsa, an older sensate from a previous cluster, felt Riley's pain and had her airlifted to a hospital.
- On Luna Magnusdottir's tombstone, her date of birth is listed as the twelfth day of January 2008. This infers the day of the crash that killed her father.