Penny, the secret daughter of Bakia (the most famous popstar of the hour), and her best friend Camilla secretly decide to audition for M.A.R.S. Meanwhile, Camilla is very happy as she's in love with Sebastian and she can't wait to meet him again. In a square, Penny hears a guy singing with his father and remains fascinated; they agree to meet and Penny gives him her lucky charm just before his father, Mitch, is mysteriously taken away by police. Penny will have to face her mother after the audition even though the result is still uncertain.

Penny and Camilla have been selected for M.A.R.S. Influenced by her manager Freddy Wolf, Bakia doesn't want her daughter to attend the school as she thinks that this could endanger her and reveal her secret. Sebastian is waiting for Penny but she doesn't show up as she has been grounded. After many doubts, Bakia allows Penny to attend M.A.R.S. Meanwhile Bruce, the owner of a toy company, seems to know Bakia's past very well.

Penny and Camilla enjoy a party at M.A.R.S. Penny meets Sebastian: she tries to hide her feelings because she knows that Camilla is in love with him, and he tells her that he didn't go to the appointment. In the meantime Camilla is more and more in love with him. Things take a bad turn at school: Lucy keeps provoking Penny, and Miss Bauer puts her in a difficult position. Anyway Penny, thanks to her friends, decides not to leave.

The acting teacher assigns a task to the students: They have to reveal their true feelings to the person they care the most. Penny stages a dialogue with her unknown father and this makes her and Sebastian grow closer. Trying to defend her mother from Tosca, Penny is about to reveal her secret but she is able to correct herself by saying that her mother is just a great fan of Bakia. Penny finds out that the mysterious instrument in the photo is a pentachord. Camilla and friends go to Raul's bowling alley, Twin Pins, and Penny finds out that Sebastian lives there.

Sebastian secretly moves to M.A.R.S. dorms. It's "Parents' Day" and Penny is disappointed because her mother isn't there. She sings very well during the performance, but she makes Lucy angry by accidentally stealing her verses. Something is growing between Penny and Sebastian. Sofia will have to choose between Mike and Nick for a partner for the dance exam. Freddy Wolf is suspicious about Bruce. During a party at M.A.R.S., Lucy convinces Penny to sing the only song Tosca has ever recorded to make fun of her. Lucy films Penny and posts the video online.

Tosca assigns a very difficult Bakia song to Penny, who finds out that Lucy framed her. Camilla advises her friend to ask her mother for help. Sofia tries to make Sebastian admit he's in love with Penny. Penny is disappointed when she comes back home to discover that her mother has just left. Camilla and Sebastian carry on a task assigned by Sean in order to overcome the boy's shyness: going around the city taking selfies with strangers. Meanwhile Mitch is released from prison and he is finally able to meet up with his son.