The twins Hanni and Nanni have been at St. Clare for a few weeks now. They have not yet made many friends among their classmates. Hanni clashes with her classmate Janet. The two compete to see who can come up with the best pranks. The victim is the shy history teacher Miss Kennedy. She leaves the classroom upset when the firecrackers that Janet has put in the oven go off. Hanni stands by Janet when the guilty party is told to report to Miss Roberts. The whole class comes together and confesses.