Atem - During a New Years Eve party up north, Atem ends up singing with a girl named Mana, and they begin to fall in love. When Atem finds out that Mana's transferred to his school, Atem can't stop thinking about her. Atem and Mana end up taking a look at musical auditions and end up singing as a way to comfort Serenity, who just got shouted down by Mai. They end up with a call back that turns the whole school topsy-turvy. Atem is then confronted by his friends about it, so Atem says what they want to hear just to shut them up, and Mana hears, so she breaks up with Atem. Atem then runs up to Mana and explains that he didn't mean what he said, so Mana and Atem get back together, and they and their friends come up with a plan to do their friends' events and the call-back at the same time through a power outage, and Atem and Mana end up with the parts.
Mana - A girl who recently transferred to Domino High. She met Atem on New Years Eve during a party just before she moved. They ended up singing and began to fall in love. Atem and Mana end up taking a look at musical auditions and ended up singing as a way to comfort Serenity after she was shouted down by Mai. This also lands the two of them a call back that turns the whole school topsy-turvy. Mana's confronted by her friends about it, but they trick Mana into believing that Atem doesn't really care about her, so she breaks up with him. Atem then explains that he didn't mean what she heard him say, so they get back together and do the call-back with their friends' support. They then end up with the parts.
Kaiba - Kaiba's a teammate of Atem's. Once Atem gets a call back with a brainiac named Mana, Kaiba tries to keep things the way they are and tries to get things back to normal by working together with Ishizu to break Atem and Mana up by getting Atem to say things that he knew Atem knew would shut them up while Mana was listening. After that, Kaiba realizes what he did and tells Atem the truth and throws his support behind his friends.
Ishizu - A new friend of Mana's. She is the leader of the brainiacs. When Atem and Mana get a call back to the musical, Ishizu and Kaiba team up to break the two up, it works, but Ishizu feels horrible afterwards. Ishizu then throws her support behind her friends and arranges a black out, so Atem and Mana can do their call back.
Joey - A teammate of Atem's. Joey's secret desire is to bake, and he dreams of making the perfect creme brule... Yeah...
Serenity - The writer of the school musical. She's very timid at first, but her new friendships with Atem, Mana, and their friends helps her become more assertive.
Tristan - A teammate of Atem's.
Tea - A friend of Mana and Ishizu. She wants to dance, and she eventually gets the chance to do what she wants after Atem and Mana get the parts.
Mai - Mai is a high school actress, and she will do anything to stay on top. When Atem and Mana get a call back, giving her and her brother Bakura competition, she gets agitated and tries to stop them by tricking Rebecca to switching the auditions to a date where they both have important obligations to their friends, but that fails, and in the end she accepts losing to them and celebrates with everyone else.