Harry's interest in solving mysteries has caught the attention of his classmates in 3B, so he challenges them to discover what he has hidden in a giant, old suitcase.
"The kids in Room 3B are asked to draw posters of things that they love, and one of them will get to share his or her poster on TV"-- Provided by publisher.
When his friend Doug is infested with head lice and Mary convinces everyone to stay away, Harry and his other friend Song Lee stand by Doug and declare war on the bugs.
"When his best friend Doug discovers his top-secret hideout, Harry enlists his friends' help to save it from being developed into an apartment building"--
Selected to join the school safety patrol squad, third-grader Mary quickly turns into a bully, and classmate Doug suspects she may be tampering with the book raffle.
Spurred on by the promise of a mystery prize, Harry and Doug are determined to win the most points on Field Day, but Harry's sneaky tactics annoy their competition, making the two boys targets for revenge.
When the origami pig that Song Lee made for her grandmother is seized by a substitute teacher, the usually well-behaved third-grader breaks a classroom rule to rescue it from the "June box."
Two days after Marvin sees a glowing green thing like a flying birthday cake in the night sky, his third-grade class is joined by a mysterious new boy with peculiar behavior.
Even though they have all come to school in holey clothes, Marvin and his third grade class manage to impress their surprise visitor--the President of the United States.