In this chapter, we learn that the girls have been instructed to steal a microscope and use it to stain cheek cells. Peter, the teacher, tells the girls that they must clean the slides with iodine and paper towels before they begin staining the cells. When the girls are done, Peter asks if they can use the mouse and the cat to help him clean up the slides. The girls agree, and Peter tells them to lock up the lab and take their phones with them in case anyone tries to harm them.