Miss Marla chooses Polvina, Ester and Marcello to represent the class in a maths challenge. Tubarina is outraged, and is determined that Marcello will have to forfeit his place for her.
As school ends, Miss Marla reveals the team for the mathematics challenge, namely Polvina, Ester and to Tubarina’s surprise, Marcello. Tubarina asks Miss Marla why she wasn’t selected and Marcello was; she is told that Marcello is the third best in the class at mathematics, while Tubarina is fourth. Miss Marla tells Tubarina that she can be a substitute, which she doesn’t believe to be a perfect solution. On the way home, Marcello teases Tubarina for being on the “B team”, much to her chagrin as she begins her sinister plan…
The next morning, Tubarina begins bombarding Marcello with difficult questions, claiming that he should be quick when giving answers. Eventually, Marcello gives in and lets Tubarina take her place in the challenge. When the girls discuss the questions they might get in the challenge, however, Tubarina finds that she isn’t prepared for them. Tubarina gets some books to study, but she panics when she is told that the challenge is the next day.
Tubarina attempts to study, but she falls asleep. Marcello looks in and laughs at the thought of Tubarina embarrassing herself, but Gummy confronts him, telling him that he thought he was nicer than that. The next morning, Tubarina is too tired to do the challenge; she worried herself sick. She lets Marcello take her place back and stays home with Gummy.
- In Who's Who, Tubarina states that she only manages to pass her tests, so it is funny how Tubarina could be fourth in the class despite evidence in this episode possibly proving otherwise.