Fifth-grader "Encyclopedia" Leroy Brown solves ten mysteries and, by putting the solutions at the back of the book, challenges the reader to do the same.

The case of Natty Nat --The case of the scattered cards -- The case of the Civil War sword -- The case of Merko's grandson -- The case of the bank robber -- The case of the happy nephew -- The case of the diamond necklace -- The case of the knife in the watermelon -- The case of the missing roller skates -- The case of the champion egg spinner.