Julia Moonglow and her twin sister Susie were not ordinary teenagers. They were born with supernatural abilities that they worked hard to conceal. Trying to keep to themselves the two sisters were close and did everyting together. One day as they were walking from school they were being harassed by a group of 4 teenage boys who happened to be stars of the football team. As they were offered to take a ride Susie turned them down. The football stars stopped their car and dragged Susie in and proceeded to try and rape her. Julia unleashed her abilities and stopped the car, when she did Susie unleashed her abilities as well and killed the boys.Knowing the rest of the town would not believe them and that they would be hunted, jailed, and imprisoned they simply left. The Moonglow twins tried to make the world understand but they were branded as criminals and killers, so in order to make due they adapted to the life of crime.
Susie tired of the life of crime approached her sister about an offer made by their nemesis Red Cowl. Confused by this Julia asks why, and the answer was to end a cycle of violence. The Deal was with Red Cowl's money and connections he would relocate them with new names and identities as long as they agree to leave the life of crime alone. The Moonglow sisters agreed, but as Julia was out trying to make more money for them to live the rest of their lives in peace Susie was called in by Red Cowl. Susie was lured into a trap by the hero, his ploy was to transfer the powers of the Moonglow twins to himself, so his powers can go past physical. As Susie struggled her life force ended up drained and she died, Julia felt this and vowed vengeance on the man who killed her sister.
After the supposed death of Red Cowl, Julia found out he was still alive. She than started visiting Red Cowl's former sidekick and now ridiculed hero, Flyboy in his sleep, and started implanting memories through her powers. Flyboy had an encounter with Julia and she showed him the truth, and took him to Red Cowl's secondary base to make a new outfit. Now going by Sidekick, Julia leads him to a path of villainy. Sidekick feeling betrayed by his former mentor and holding Red Cowl responsible for his despair teams up with Julia in crime and romantically to exact their revenge on the hero known as Red Cowl.
Julia Moonglow's powers are never explained, except for the fact that they border on the supernatural. Her powers strengthened hen near her sister and diminished when away from each other.