Makoto was a curious second-grader who loved solving puzzles and mysteries. One day, he noticed that his favorite snacks were disappearing from the kitchen cabinet, and he was determined to find out what was going on.

Makoto started by gathering clues. He noticed that the snacks would go missing after his family's pet dog, Kuro, was left alone in the house. Could Kuro be the culprit? Makoto decided to set up a trap to catch the snack thief in the act.