Mildred is warned that if she doesn't behave, she may not be allowed to go on the half term trip. Mildred does her very best to behave. No one believes she can manage it. On the last day before the trip, Mildred feels that she can do it. It's also Miss Cackle's birthday. Just before they enter the hall for the celebrations, Enid drags Mildred into a cupboard and Ethel locks the door. Mildred is upset, as she now believes that she won't be going on the trip after all. They see a window from which they might be able to escape, but it's too high. They find an old broomstick and decide to fly out. The window ends up leading straight to the hall where the birthday celebrations are taking place!