Michael Fry 
Odd Squad: Zero Tolerance [EPUB ebook] 

The Odd Squad are back! After taming the school's biggest bully, Nick, Molly and Karl expect to bask in Safety Patrol glory. But without a bully to set straight, all they're left with is helping sixth graders cross the hall and reminding everyone that Jell-o meat stains. Enter new kid Simone, who shakes up the team. Soon Nick is facing trouble. Big trouble. Explusion-level trouble. Which would mean repeating seventh grade… He needs help, and fast, because if there's one thing worse than being the shortest seventh grader in the history of the world, it's having to go through it twice.