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.

After Joe makes a wish on an amulet and becomes the protector of undead pets, he is visited by the undead hamster Dumpling who can't move on until he reveals the truth about his death and Joe agrees to help.

When summer arrives, Humphrey, the pet hamster of Longfellow School's Room 26, is surprised and pleased to learn that he will be going to Camp Happy Hollow.

"It is Princess Harriet Hamsterbone to the rescue when Heady the hydra's egg is stolen, but her search leads her to a castle accessible only by a rat with a very long tail"--

Harriet Hamsterbone is trying to be the perfect princess, but life at the royal palace is dull. When she learns from her parents that she is cursed to prick her finger on a hamster wheel at the age of twelve and fall into a deep slumber, Harriet believes she is invincible until that age and sets off on an adventure with her friend Mumfrey the quail. However, when things go wrong at home, she must find a prince to help her set things right.

"During a creative writing unit at Longfellow School, the students in Mrs. Brisbane's class practice using their imagination with their very own writing journals--and Humphrey finds out that writing from his imagination is harder than it looks"--

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.

"Sam Gibbs and his super-strong tiny buddy, Hamstersaurus Rex, keep encountering creepy abnormal objects like a floating sports jersey and a runaway go-kart. Could bizarre mutant animals be the cause." - back of jacket.

When flying ninja squirrels invade the school, the Super Pet Superhero League must go into action to find out what is going on.

"To Humphrey and the students at Longfellow School, spring seems impossibly late this year. Fortunately, planning a school Family Fun Night keeps the students (and classroom pets) busy as they look for signs of the changing seasons"--Provided by publisher.