In the middle of the night, Bianca is awakened by the sound of someone tapping on the door. She asks to be let in, but the door is locked, and she is unable to open it. When she opens it, she discovers that the door has been left open, and that someone is trying to break in. She is able to open the door by tapping on it with her bare hands, but she cannot open it by tapping her foot. When the door opens again, she realizes that someone has broken in, and the person who broke in is not able to get in. The door is unlocked, and Bianca is allowed to enter.