Ich, Tessa und das Erbsengeheimnis

Paul is a passionate private eye. When new neighbors move in next door, he decides to keep an eye on the young girl Tessa. And indeed, she turns out to be quite peculiar. Why is she always going to school via detours? What's the purpose of the peas, and what is she hiding in her red suitcase? Why doesn't she play badminton with the other kids? Paul risks everything to find out what's going on. 

This series is recommended for K-12 students.