Main article: Violetta
Violetta Castillo is a teenage girl who is unaware of her very special talent for singing. She inherited this talent from her mom (Maria), a famous singer who died in a car accident. Germán (Diego Ramos), her dad, is a very successful man who travels a lot and loves his daughter, despite being strict and overprotective. Blinded by sadness, he decides to keep her past and her mother's fate from Violetta, worried that she might follow in her footsteps. After the accident, they both moved to Madrid and he raised her alone, with hardly any contact with other children of her age. Germán is aware that Violetta is a very talented musician and he encourages her to take piano lessons but keeps her away from singing. Everything changes when they return to their homeland in Buenos Aires. There, Violetta starts taking piano lessons at 'Studio 21' (later On Beat Studio), a prestigious music school. She meets Angie (Maria Clara Alonso), her new teacher, governess, and secretly her aunt (sister of Violetta's mother, unbeknownst to Germán) who helps her to realize her talent. Angie fears that if she tells Violetta or Germán the truth, Germán would take Violetta away to another country, where she could never see Violetta again. Violetta falls in love with Thomas (Pablo Espinosa) but Francesca (Lodovica Comello), her new best friend, already liked him. Ludmila (Mercedes Lambre), the richest and most arrogant girl Studio 21, also falls in love with Thomas, angering Leon (Jorge Blanco), her old boyfriend. Later, Ludmilla and Thomas start dating. Leon got furious and, to teach Ludmilla and Thomas a lession, he decides to date Violetta. Contrary to his plans, he begins falling in love with Violetta and she starts to fall in love with Leon, which irritates Thomas and Ludmila, who are just beginning to date. Germán is engaged to Jade (Florencia Benitez), an unintelligent woman who, though very ambitious, is callous and hates Violetta. Jade does everything to marry Germán because she loves him truly, but Matias, her older brother, wants her to marry Germán because of his money because he got broke. Violetta has never agreed with this and always argues with Jade. Later, Jade discovers that Violetta's secretly studying music in Studio 21, and makes Machiavellian dealings with her: if she encourages Jade's marriage to Germán, she won't tell Violetta's secret to Germán. In the end, Germán discovers that Violetta studies in the Studio and that Angie is actually her aunt and who always helped and covered for Violetta all along. Germán decides to take Violetta away, but thanks to Angie he understands the passion of Violetta at the last minute and decides to stay in Buenos Aires, allowing Violetta to continue at Studio 21. In the end Thomas goes back to Spain as he has the opportunity to make something of his music and Ludmila makes peace with everybody (leaving doubts as to whether she really was sorry). Leon promises himself to forget Violetta.
In the second season, Violetta starts falling in love with Leon and he feels the same for her. They start to date, but Diego (Diego Domínguez), who is new at Studio 21, steals a kiss from Violetta. Ludmila continues to be an unkind and glamorous girl who does everything to get what she wants: she blackmailed Diego to pretend that he loves Violetta, telling him that if he will do that, she will tell him who is his father, who abandoned him. Marco does everything to date Francesca, who later starts falling in love with him. Camila and Broduey start the season fighting, but in time, Camila kisses Maxi, DJ gets to make Camila jealous with Sebas (Rock Bones) until they get together at the end. Naty, Ludmila's best friend, and Maxi also split up at first, but come back in full force. Ludmila starts falling in love with Federico and get together at the end. Diego finds out that his father is Gregorio, a selfish teacher that works at the Studio. Diego is very mad at him, because he abandoned him when he was a child; at the end they make peace. Angie goes away to France, leaving Germán alone. Esmeralda is hired by Jade and Mathias to win Germán over and steal his money. However, on their wedding day, Jade reveals that Esmeralda is a scam. The two are arrested and Matías starts dating the deputy who arrested him, Marcela Parodi. Leon suspected Diego all along, and found proof that Diego and Ludmila were together to make Violetta sad and humiliated on her big performance when they were going to say that Diego never loved Violetta. Leon shows the footage of proof on his cellphone to Francesca, but Violetta overheard. Violetta started crying during her performance without any strength to sing. But, Leon got on stage and started singing "Podemos" with Violetta. Violetta and Leon got back together, and in the end, after all that passed, their love was stronger than ever.
After closing with You Mix, the studio cast of On Beat went on a major world tour, which had been successful in Europe. Violetta and her friends had to return to Buenos Aires for their last year of school. With dreams and individual ambitions multiplied by fame, the group began to crumble, putting Studio On Beat in danger. Gery, who falls in love with Leon, and Clement (also known as Alex), who falls in love with Violetta, are introduced at the beginning of the season. Violetta and Ludmila were forced to share the same roof when Germán and Priscilla, mother of Ludmila, start dating and later get married. Violetta and Leon become separated, but still love each other, but Alex and Gery will do anything to keep them separate, since they are passionate, respectively, for Violetta and Leon. Marco went away, and Francesca and Diego fell in love with each other. But, Francesca was afraid of Violetta finding out (since Diego regretted what he did to Violetta during the previous season) and decided to keep their relationship secret. With the death of Anthony (the previous director of Studio 21), Pablo exits Studio On Beat at the end of You Mix sponsorship, the site slowly went bankrupt and it was up to Gregory, the new director, Angie (who returns in this season) and Bob, along with the help of Germán, save the studio. Ludmila starts to become a better person and when forced to choose between staying in the Studio On Beat or be a star, she chooses the Studio. In order to spy on Leon, Violetta and Francesca masqueraded as Roxy and Fausta, but Leon fell in love with Roxy, and Violetta was forced to tell him the truth. The series ended with Germán marrying Angie.
