Horrible Harry thinks he?s the world?s second-best detective?second only to Sherlock Holmes, of course. But the rest of the kids in Room 3B aren?t so sure. So he?s determined to prove himself by solving the latest mystery at South School?how to win the new cafeteria contest. He knows the cafeteria lady is using a special mathematical code, but can he crack the code before his classmate Mary tattles on him again? Or will the case go cold right before Harry?s eyes?

Horrible Harry thinks he?s the world?s second-best detective?second only to Sherlock Holmes, of course. But the rest of the kids in Room 3B aren?t so sure. So he?s determined to prove himself by solving the latest mystery at South School?how to win the new cafeteria contest. He knows the cafeteria lady is using a special mathematical code, but can he crack the code before his classmate Mary tattles on him again? Or will the case go cold right before Harry?s eyes?

The kids in Room 3B are holding a Sharing and Caring Tag Sale to earn money for charity. Song Lee and Ida are selling friendship bracelets, Doug is selling books, and Sid is selling delicious, fresh-baked chocolate chip cookies. But something else is on Harry's mind: his grandmother is having money trouble, and Harry wants to help. So he comes up with a plan to raise money for her. The problem is that Harry doesn't realize his plan involves stealing from the class's charity collection! How can Doug stop his friend from becoming a horrible thief? Could the answer come from one of Sid's delicious cookies?

Another fun mystery starring Horrible Harry, and this time he's calling the shots! Harry has always loved solving mysteries, and now his friends in Room 3B have learned to love it, too. So Harry challenges them to figure out what he has hidden in his giant, old suitcase. Led by a very determined Mary, the kids take turns solving clues and piecing the mystery together. Their hunt leads them from the classroom to the library, and even to Harry's grandfather's nursing home. Will they be able to solve Harry's mystery? Or will things go horribly wrong for the novice detectives?

Horrible Harry has always loved insects, especially digging in the dirt for them. And, recently, he's discovered a new favorite: earwigs! But when he tries to tell his friends about these critters, only Song Lee listens. So when Miss Mackle assigns groups in Room 3B to act out different fairy tales, Harry sees an opportunity to teach the class about his favorite bug. Will they think his play is hilarious...or horrible?

After four days in a row of indoor recess, Miss Mackle's students are bored-until Harry decides to solve the biggest mystery ever in Room 3B! There's a locked closet in the classroom that's been sealed off for years, and he wants to know what's inside. So Harry drafts Doug, Song Lee, and the rest of the class to help him investigate. Their search reveals many surprises-from a hidden trapdoor to...eyeballs! What secret treasures does the closet hold? Is it something more horrible than even Harry can imagine?