Fourth-graders Drake Doyle and Nell Fossey combine their detective and scientific investigation skills to solve a variety of cases, involving a noisy garbage can, endangered frogs, a stuck truck, and a mysterious love letter. Includes a section of scientific experiments and activities.

Now in fifth grade, Drake Doyle and Nell Fossey continue to combine their detective and scientific investigation skills to solve a variety of cases, involving a noisy laundry chute, a ruined flower show, and a ghost.