Dee have a hunt...
Have him create his list of clues - you know: clue #1 - look in the medicine cabinet and locate string; clue#2 - follow string to end to find clue #3, and so on ... if you can sneak his clues it would be fantastic, because you could play off of them and have yours end in the same spot that his does, where he'd find you hiding bare behind a big posterboard heart (and nothing else) if he follows your clues correctly.