The world-famous Flying Graysons of Haly's Circus are two of only three people on Earth who can perform the quadruple somersault. The third person, of course, is their daughter, Rachel Mary Grayson.
Ellie the Girl Wonder.
She joined her parents up on the trapeze at the surprising age of seven, but had been a part of their acrobatic act since she learned how to walk. Ellie was a bright star in the circus, flitting about the circus grounds always with a smile, her ponytail bouncing behind her, whether it was playing with her fellow circus brat, Randal, and the clowns, or, like one fateful day when she was eight, heading to the showers after rehearsal.
That autumn, Haly's Circus had been asked by Wayne Charities to perform as part of one of their benefits. The day before the big show, Ellie stumbled upon Mr. Haly kicking out a mobster by the name of Tony Zucco trying to extort "protection money" out of him. She saw Zucco leave and even though he told Mr. Haly that he'd regret not paying, she didn't think much of it beyond its strangeness until the night of the show. Just before taking the center ring with her parents, Ellie saw Tony Zucco leaving the big top dressed as one of the roustabouts. She tried to tell her parents, but it was time to go on for what would prove to be The Flying Graysons' final show; Ellie watched John and Mary Grayson fall to their deaths when a cut trapeze wire finally gave way under their combined weight.
She gave her statement to then-Lieutenant Jim Gordon and then it was just a question of what to do with her. As far as Gordon was concerned, allowing her to leave Gotham with Haly's was out of the question since Ellie was a key witness and Zucco would undoubtedly come after her; they would be able to keep her under police protection if she stayed in Gotham, but that meant sending her to an orphanage. It was Bruce Wayne, CEO of Wayne Enterprises and who had organized the benefit and been present that night, who offered up an alternative solution.
The next day, Haly's Circus had to start packing up and heading out to the next city and Ellie had to say goodbye to her family. She packed everything she had from her parents' wagon and before she knew it, she was on her way to Wayne Manor. Those first few weeks were tough, Elle thrown into a completely new situation in a city she'd only passed through on the fair grounds with a man whose name she'd only learned at the benefit performance; for Bruce's part, well he was a young businessman who was not only working most of the time, he also had no idea how to relate to a young girl. It was Alfred who gave him the push that he needed, reminding him that he'd been a child despairing over the loss of his parents once too and that all he'd really needed at the time was a friend. After that, Bruce started making more of an effort to reach out to her -- buying her tickets to the Gotham City Ballet, actually letting her work out some of her trauma and lingering guilt talking to him and assuring her that the pain would get better, he even began teaching her some fencing and martial arts when she noticed the equipment in one of her explorations of the huge mansion and expressed an interest in learning.
Elle took fairly quickly to it, which might have contributed to her confidence in being able to track down Tony Zucco on her own when she overheard Jim Gordon telling Bruce that sources were telling them that Zucco was getting ready to skip town. That night, Elle lifted bus fare from the spare change in Bruce's suit jacket pocket, tore out the picture of Zucco that had been running in the paper since the night her parents had died, and snuck out of Wayne Manor to find the man who'd killed her parents. Through a bit of detective work and luck (and being adorable), Elle was pointed in the direction of an empty warehouse by Gotham Reservoir where Zucco had been seen coming and going. She'd only meant to make sure he was there and then call the police, but she accidentally crushed a can underfoot, alerting Zucco to her presence and delivering the last loose thread right into his lap. Elle fought back, but, being only eight years old, it didn't take much for Zucco to overpower her. Though Batman swooped in to save the day, a rusty railing at the edge of the reservoir prevented him from capturing Zucco that day, instead diving into the water to save Elle.
Batman took her back to the Batcave and revealed his secret identity to her, clinching her permanent residence at Wayne Manor. But when she expressed the desire to help him fight crime in Gotham, he succinctly refused. She was too young and inexperienced and Gotham City's criminal underbelly was far too dangerous.
So she trained herself. Elle began practicing every day when she had free time, falling back into a training regime similar to the one she'd had with her parents at the circus. She used everything that Bruce had taught her so far and snuck down into the Batcave to use the equipment down there; she became more aware of her surroundings, taking every opportunity to right wrongs when she saw them in school or on the street, to prove to Bruce that she was capable and would make a great partner. It was when she started sneaking out at night to follow Batman and help him from the shadows (across town) that someone in Wayne Manor finally decided to take some initiative.
One afternoon after school, Elle went up to her bedroom to change out of her school clothes and into something more comfortable for her training exercises and found, to her surprise and delight, one of the designs she'd doodled in her notebooks of her eventual superhero costume had been brought to life. It had been modified a bit to add more protection, but otherwise was just the way she'd imagined it to be. And she knew what it meant when Bruce gave Alfred a Bat-Look when she bounded into the Batcave wearing it when he was getting ready to go out on patrol. He still refused to allow her to patrol with him, but that didn't stop Batgirl.
When Harvey "Two-Face" Dent announced the kidnapping of a socialite's twin newborn sons, Batgirl was right there to help Batman catch them when Two-Face threw them from opposite sides of the roof of the socialite's apartment building. Unfortunately the newborns were actually dolls rigged with sleeping gas and when Batgirl woke up it was in a warehouse down at the docks. She was tied up, but could see Batman and two other men tied up with hoods over their heads -- one was the mobster Maroni who had ruined Harvey Dent's life and turned him into Two-Face, the other was Judge Watkins, the man who had let Maroni go free.
Dent had initially intended to make Batman choose who was killed first and then to kill Batman, but the new sidekick appealed too much to Dent's fixation on duos. He gave Batgirl the choice: Heads Maroni dies first, Tails Watkins gets it. While Batgirl was hardly cool-headed, she at least managed to have the wherewithal to try to distract Two-Face while Batman worked on escaping his bonds. She waffled on choosing heads or tails, then convinced him to risk double or nothing on a two-out-of-three coin toss. Eventually he became frustrated enough to start working her over, but by that time it wasn't long before Batman had escaped and fought off Two-Face, releasing Batgirl and letting her take care of Two-Face's twin goons before releasing Maroni and Watkins.
Lieutenant Gordon didn't seem pleased when he showed up to find the nine year old girl working alongside Batman and with a few obvious injuries; but Batman assured Gordon that Batgirl was worthy of the name and had helped save three men's lives that night. Elle hadn't been that proud since the first time she'd successfully performed the quadruple somersault.
Things changed quite a bit in Wayne Manor after that. Elle began her real training for a life of crimefighting and Batman finally allowed her out on patrol with him, much to the chagrin of later-Commissioner Gordon. Batgirl started taking down villains and criminals almost as easily as Batman himself, gaining her own infamy among the criminal underbelly of Gotham. She still had quite a ways to go to prove to him (and a decent proportion of Gotham's population) that she could handle herself, but she was up to the challenge.
Eventually she started meeting other heroes and their sidekicks -- Green Arrow and Speedy (Royce Harper), Wonder Woman and Wonderkid (Donna/Don Troy), Aquaman and Aqualass (Gwen), Flash and Kid Flash (Wendy West) -- and they started up their own teenaged version of Gen 1's Justice League, the Teen Titans.
They fought and battled and saved the world together and became role models for youth everywhere.. Until they started getting older and things started getting way too complicated for a bunch of kids to figure out and work through on their own. Elle, Royce, and Donna had a falling out when it came to light that Donna was born male but had been raised female and hadn't warned Royce before they started getting intimate. Elle and Royce were both terrible to Donna, Gwen couldn't suffer the ignorance and immaturity being displayed, and Wendy didn't have the patience, so they all went their separate ways.
At some point after that, Elle rejoined a new team of Titans made up of Wildfire/Koriand'r, Beast Girl (Gail), Cyborg (Val Stone), and Raven (Ray). Meanwhile, at home, she was attending college and developing a relationship with Jim Gordon's aspiring detective son, Bobby, secretly the Bat-associated Robin who'd begun fighting crime with them not too long before the first Titans broke up.
When Elle eventually quit/was fired from being Batman's sidekick, she went on a soul-searching journey and eventually came back as the new hero, Nightwing, only to find Batman had taken on a new Batgirl, Jayce.