The sisterhood has entered a new school year, and right from the start it's a bit too much: a mountain of learning, a strange new boy in class, Mrs. Marie in the hospital... and one big mystery that will put the girls in real danger this time. Although they have a magical cat Fabiola who always helps them with everything! But this time he will be busy, so Bára, Ela and Míša may have to fend for themselves. Will they get on the trail of a man who doesn't shy away from hurting animals?