Franzi is in love - should she really confess her feelings to her crush? When he flirts with someone else, Franzi decides it's better to forget him. But that's not so easy... Why is being in love so chaotic? Luckily, there's a new case for the three: Franzi's math teacher has a secret involving two of her classmates, who are behaving quite mean towards him. What do the three of them have to hide?.