In the vibrant city of Starlight City, Albert Carter, a dedicated environmental scientist, accidentally gains extraordinary powers after a lab accident involving a rare meteorite. With the ability to manipulate cosmic energy, he transforms into the superhero Astra. As he learns to control his powers, strange occurrences plague the city, including mysterious disappearances linked to a dark figure known as Ultra.
Initially at odds, Astra and Ultra reluctantly join forces to investigate the rise of the Dark Ones, individuals corrupted by negative energy. As they uncover a conspiracy led by Albert's mentor, Dr. Mira Lane, who has been experimenting on people to create the Dark Ones, they must confront their own beliefs about justice and power.