Before they leave, the rats must fulfill their promise to Mrs. Frisby to move the cinderblock that is home to her and her children. They do so with much ingenuity and thoroughness, using teamwork and a complicated system of pulleys, hooks, and ropes, and attending to every detail, including covering the hole where the cinderblock used to be to allay suspicion, and reassuring the children so they will not be frightened. Only after the rats have completed the job do they consider their own survival, planning their own escape from the exterminators who are due to arrive.