Summer is in session, and that means all the neighborhood patrols, soccer games, and snacks the boys can handle. But things take an unexpected turn when a new group of heroes, known as the Hero Club, approach Damian and Howard with an unusual offer--an invitation to help unmask the corporation planning to build a recycling factory in their favorite park. If that weren't enough, Batman has been acting strangely and disappearing for stretches of time. And there are ninja everywhere... What could possibly be going on?