Humphrey the hamster is the class pet of Room 26 at Longfellow School. He is hurt to learn that Ms. Morgan McNamara (known as Ms. Mac), the teacher who purchased him, is going away and that she will be replaced by Mrs. Brisbane, who is returning. Before Ms. Mac purchased him, Humphrey thought he would never get to see the world outside Pet-O-Rama. Once she set Humphrey’s new cage up at her home, Ms. Mac gave him a small pencil and notebook. Within a week, Humphrey could read and write.

Humphrey got to know the students in Room 26, and life suited him there. He would go home with Ms. Mac at night. He lived content for six weeks, without “an inkling—until this morning—of the unsqueakable thing she was about to do” to him (5). Ms. Mac was a substitute teacher; she took over Mrs. Brisbane’s class while she took care of her injured husband.

Mrs. Brisbane is not pleased with Humphrey’s presence in the classroom. Ms. Mac assures her that the students know how to take care of him. Ms. Mac says her goodbyes and whispers to Humphrey not to forget her.