When Humphrey the hamster returns to Mrs. Brisbane's class after the winter break, a new class pet and some other surprises give him an opportunity to reflect on the meaning of friendship.
After learning about Sherlock Holmes, Humphrey the classroom hamster follows clues to try and discover why Mrs. Brisbane is gone and Mr. E., a fun but not very educational substitute, is taking her place in room 26 at Longfellow School.
