Despite protestations, Dennis is assigned to Sgt Slipper's command for Take A Kid To Work Day. Grumbles all round - until reports start flooding in of garden-gnome thefts all over Beanotown... this might not be so boring after all! However, due to his ability to think like a master prankster, Mayor Scrimp tasks Dennis with finding the culprit - or copping the blame himself! Luckily, they have their very own police dog to sniff out the clues, so the menaces go into full on detective mode to find the gnome-napper and solve the case.