Sycorax and Caliban are two characters from Shakespeare's play The Tempest. Sycorax is a powerful and sadistic witch. She is also the mother of Caliban, who is one of the main antagonists of the play. Mrs. Baker named her two rats after Shakespeare characters because she loves Shakespeare. Most of the book is about the relationship between herself and Holling Hoodhood, a student of hers that is forced to spend Wednesday afternoons in her classroom. He must go to her classroom because he is neither Jewish nor Catholic. Those two groups of students go to their own religious studies area on Wednesday afternoons. Mrs. Baker decides that it would be good for Holling to read Shakespeare during their Wednesday afternoons. Holling disagrees, but learns to love reading Shakespeare and deeply respect Mrs. Baker. Through his reading of Shakespeare's plays, Holling learns that the class rats are named after two evil characters in The Tempest.