A giant department store on a rainy day is the perfect place to get completely lost. Nate the Great usually relies on his trusted dog, Sludge, to help him solve every single case. But this time, the world's greatest young detective is facing his worst nightmare because Sludge is the one who is missing. Separated in the middle of a massive and crowded store, Nate frantically searches high and low for his furry best friend. He dodges salespeople who have spotted a wet and slippery dog running through the aisles, but every single clue seems to lead to a frustrating dead end. Without his canine partner to help him sniff out the answers, Nate feels entirely stuck. He must use all of his logical thinking and remain calm under pressure to reunite with his dog. This suspenseful and heartwarming mystery highlights the unbreakable bond between a boy and his best friend.