Ten brief cases allow the reader to match wits with ten-year-old crime-buster, Encyclopedia Brown, as he locates stolen jewels, retrieves a stuffed tiger, and more. Solutions are included at the back of the book.

Young Sherlock Holmes, committed to solving crimes after his mother's death, is visiting his father at work when an aerialist, practicing a high-trapeze performance at the legendary Crystal Palace, falls to the ground, landing at Holmes' feet, and uttering two cryptic last words that send the boy on a dangerous search for answers.

With a young Sherlock Holmes immersed in despair, the only thing that can rouse him from this blackness comes when he uncovers a sinister plot unleashed by Malefactor.