It's Janet's birthday and the girls are planning a big midnight feast. Kathleen, who is not exactly popular in her class, gets into trouble when she is also invited but has no money to buy a present for Janet and contribute to the expenses of the party. Suddenly, however, she becomes unusually generous. Meanwhile, strangely enough, the cases of missing or lost purses are piling up. Nanni is put up for the first lacrosse team together with Kathleen and no longer has time to think about the incidents.