Gyan Ganga School is infamous for its large debt to the grand Gateway School, but Gyan Ganga still believes it was an injustice and a falsehood. Four sixth-graders at Gyan Ganga—Meera, Abhinav, Darshini, and Devesh—are a group of misfits with good grades. And their world changes when they join the Detective Club.

Their first challenge is to gather evidence for the mysterious case known as the Great Debt and demonstrate the school's innocence. As they work on their project, they discover a world of logic and puzzling mysteries and venture their way through it. But will they show the court that a group of middle graders can find the evidence that could change their school's fate—and possibly theirs?