Double the excitement! The three ??? are working on a secret invention. But suddenly, it has vanished without a trace. Luckily, the detectives have a brilliant idea: they absolutely need magic ink! Will their plan succeed? Can they catch the thief? Justus, Peter, and Bob don't believe that a monster has wreaked havoc on the playground. Who is really behind it? Two cool cases to learn reading in one volume. Read the stories and solve exciting puzzles at the end of each chapter. Join in the fun and help the three ??? with their investigations in Rocky Beach interactively. Featuring great illustrations and large print for beginner readers.