Sora Naegino is the main protagonist of the anime Kaleido Star. Born and raised in Japan, Sora's dream is to become a true Kaleido Star. Her Japanese voice actress is Ryo Hirohashi while her English voice actress is Cynthia Martinez.
Sora comes to America to join the Kaleido Stage, a theatre company located in Cape Mary, California. When Sora was very young, she and her parents came to Kaleido Stage to see their production of Alice in Wonderland, which helped give birth to Sora's dream of becoming a Kaleido Star. Shortly after, both of Sora's parents passed away and she was taken in by her aunt and uncle, who didn't have children of their own. During the rest of her life until she arrived in America, she trained well in hopes of becoming a member of Kaleido Stage. Her aunt and uncle were both hesitant to let her go but Sora manages to convince them otherwise. When she arrives, she becomes lost in the bustling city and stops for directions. There, she meets Kalos Eldos, who she believes is a pervert since he is examining her legs at the moment she asks for directions to the stage. As Sora is disturbed by Kalos' actions, her bag is stolen and she performs amazing feats through the streets to get her bag back.
Once getting her bag back, she is brought to the Police station under the belief that she ran away from home. But after an understanding, one of the officers, Jerry, drives Sora personally to Kaleido Stage wishing her the best of luck in her audition. However, she arrives too late and she asks for a chance to audition. But Sora's idol and Kaleido Stage's top star Layla Hamilton rudely rejects her saying that she should leave since she missed her audition. Outside, Sora feels defeated and plans to go back home. She meets Ken Robbins, one of the stage helpers who takes her on a tour back stage. She accidentally "saves" one of the performers from a balloon falling down on her. The performer is injured and cannot go on. But Kalos returns, to Sora's shock that he is the boss, and sends Sora on stage to replace the performer. On stage, Sora is completely embarrassed and cannot perform straight. But by luck, she manages to make it through and even receives help from Yuri Killian, the other top star and Layla's partner.
After the performance, Layla criticizes her on her lousy performance and tells Sora to leave. But Kalos has other plans for Sora, which Ken makes clear when he tells Sora that Kalos has allowed her to join Kaleido Stage. When she moves into her new dorm room, she meets Fool, the Spirit of the Stage who only the chosen few can see. And thus begins Sora's long and hard road to becoming a Kaleido Star.
During her time at Kaleido Stage, Sora is first rejected by everyone because they call her way of being accepted into the company as "getting in good with the boss" while they had to work hard and she is doing poorly in the training sessions. But soon after daring to attempt Layla's Golden Phoenix maneuver, in which she would be forced to leave if she failed to do so, she makes new friends in Anna and Mia. She manages to almost perform the maneuver and earns Layla's approval to stay at Kaleido Stage. She soon starts to make more friends like Sarah Dupont, the dorm supervisor, Marion Benigni, a young girl whose mother was a trampoline performer, Johnathan, a baby seal and Rosetta Passel, a diabolo prodigy who had trouble making the audience enjoy her performances. During Sora's beginning, Ken becomes Sora's personal trainer to help her with the basic skills she needs to improve on. At one point, Sora's adoptive father comes to visit and convince her to come back home. But ill fortune strikes when he has to be rushed to the hospital during one of Sora's performances. She still goes to see her father and agrees to return home. But at the airport, her uncle sees how much Sora loves being with her new friends and she is allowed to stay as he returns home. When Layla left for a movie filming, Sora was casted alongside Anna as a lead role for The Little Mermaid performance as the mermaid.
During this time, Sora starts watching Layla's performance from the last show and starts to try and mimic her movements. But when she tries that during the show, she doesn't receive the applause she hopes for. Feeling like that failed, Sora began trying to do her own thing during the show, ad libbing during the performance and confusing her fellow performers. She then asks the audience for their opinions about her performance after the show. At this point, the crew is just angry at her and scolds her, telling her to try and pass ideas to them before doing ad lib in the middle of a show. Sora feels so lost after that point. But she starts wondering what her character, the mermaid, must be like. She starts to live life as a mermaid, which included trying to move around without her legs and playing in the water with Johnathan, even to the point of sleeping in her costume. She then pitches her ideas to the crew and the other performers seem intrigued by Sora's suggestions. And when Layla came back to see Sora's show after the many bad reviews, she's shocked to see that Sora changed the sad tale into a happier story where everyone is more into their characters and are really having fun. After Cinderella and The Little Mermaid, she gets a chance to star in the production Arabian Nights alongside her idol Layla (it was a suggestion by Mr. Kenneth that Sora be Layla's partner). While Layla is against the idea of performing with Sora instead of Yuri, Sora's hard work and determination soon show Layla that there is something inside of Sora that she doesn't have.
With Layla gone, Kaleido Stage is losing audience even with the addition of the incredible Leon Oswald, who performs for short whiles and then leaves during the performance. Sora meets May Wong, a new addition who declares herself Sora's rival and blames her for ending Layla's career. While Sora plans to throw the new performers a welcoming party, she runs into her old friend Rosetta, who wants to follow in Sora's footsteps and become a trapeze artist. Throughout the first half of the season, Sora battles with May in a fierce rivalry to become Leon's partner. In an ice skating competition, May wins and becomes Leon's partner for Dracula, making this the first time Sora had a bit part in a performance since Cinderella. But while she felt defeated, her mood soon rose after she helped her friends create the Children's Stage, when Dracula began scaring the children in the audience. On it's debut appearance, Sora performed with Marion and she once again was back to her old self again.
Later, Sora is offered a chance to perform in a Broadway performance called Salome In Vegas, which has her old friend and idol Layla as the star. Even with May sneaking along, Sora and Layla's reunion is a heartfelt one (mostly for Sora) as Sora is with her dear friend once more. After seeing Charlotte and Julie again, meeting Cathy and learning how she and Layla are like partners now (something that hurt Sora's feelings), she performs with Layla and makes the performance a success while competing with May as a background character. But Layla tells Sora that she seems to be losing the same feeling she had when they were partners. Later on, during a performance at Kaleido Stage, Leon sprains May's arm and leaves her feeling rejected and hurt. Sora sees this as a chance to be Leon's partner for the upcoming Circus Festival, but May pulls through her injury and overshadows Sora again to be Leon's partner with her Demon Spiral. Sora finds an loophole in the admittance system to the Circus Festival, in which both of the winners from last year are given Phoenix Tickets to enter, she turns to Layla's partner Yuri. They train for The Angel's Maneuver, the best bet against May and Leon's Demon Spiral. But when it comes time to perform at the festival, Sora's heart is broken when she sees two other performers who she though were her friends attempting their maneuver and failing. When Yuri and Sora go on, she is seen crying on stage and she drops from the festival while May and Leon stroll away with the win. After which, Layla tells Sora that she is disappointed in Sora in the same rude voice she used on her at the start.
Feeling defeated, Sora leaves Kaleido Stage and May takes her place as the best star. But while she is home in Japan with her family and friends, she realizes that her dream is to become the Kaleido Star - not by fighting other performers, but by creating her own stage with no conflict where the audience and cast's hearts are one. When Sora returns to Kaleido Stage and starts down this path, Leon soon sees that Sora is his true partner (she reminds him so much of his younger sister Sophie). Through hard determination and pain, and even winning May's friendship, Sora and Leon become the leads in Swan Lake to perform the Angel's Maneuver. But Layla returns and challenges Sora for the lead. While Layla seems to match Sora, she soon realizes that Sora's skills have far surpassed her and she wins the challenge. And when it comes time for the performance, Sora's Angel Maneuver brings together everyone's hearts together and her stage is born, making her the new Kaleido Star.