Lenny, Mike, and Other Mike are back in school for the glory that is seventh grade, and this year, Mike is determined to make catcher on the middle-school team. When Mike's hard work pays off and he wins the coveted postition, Lenny is a little jealous, but he'll settle for being the team's unofficial announcer.

The team has a brilliant new pitcher, Hunter Ashwell, and though he's a bit of a jerk, he and Mike have a great pitcher/catcher dynamic that could make the team champions. But things take a strange turn when Hunter's perfect pitching streak goes downhill, and Lenny suspects foul play—specifically, someone stealing Mike's catcher signals. But who could be responsible, and why?