George and Harold and their doubles, Yesterday George and Yesterday Harold, have been taking turns going to school, but when the doubles fall prey to their gym teacher, Mr. Meaner, and his method of mind control that turns students into attentive, obedient, perfect children, it is up to original George and Harold to strike back.

Young Joe and Ravi think they have nothing in common. Joe has lived in the same little town his whole life, but recently his best friends moved away, leaving him alone. Ravi and his family just moved there from India, and he just wants to fit in. When the two boys run afoul of the same bully, they discover they do have something in common after all, and scheme together to take control of their lives.

When George and Harold hypnotize their principal into thinking that he is the superhero Captain Underpants, he leads them to the lair of the nefarious Dr. Diaper, where they must defeat his evil robot henchmen.

When Hailey becomes her new classmate, Eva the owl really wants to be friends with her--but Hailey seems to want nothing to do with her. Worse, Hailey seems to be stealing Eva's best friend Lucy away.

Ryan wants to form a curling team at school with A.J. and Andrea, but soon trouble amongst his teammates threatens to end their season early.

"A.J. is graduating! But a crazed PTA president is turning second-grade graduation into a huge affair complete with fireworks and skywriting. By the time this graduation ceremony is over, there won't be any time left for summer vacation!"--Jkt.

On the third day of school, a young boy is sent to the principal's office and thinks about all the horrifying rumors he has heard about her.

Her daddy in tow, Trixie hurries to school to show off her one-of-a-kind Knuffle Bunny. But an awful surprise awaits her: someone else has the exact same bunny!

Alexander has just moved into Stermont, but the elementary school is being torn down, his new classroom is located in the hospital morgue, a notebook he finds is full of information about monsters--and everywhere he turns there are spooky balloon men determined to attack him.

Eva's class is putting on a play and she is disappointed that she didn't get the starring role; instead she is the understudy. Things are going well until the set falls apart, everyone forgets their lines, and the main actress hurts her leg. Eva encourages everyone around her, and when she has to fill in for the star, she gets her chance to be in the spotlight.