The Invisible Man has a problem. His dog, Spot, is missing. Complicating matters, Spot is also invisible. So the Invisible Man turns to Nancy Spector for help. Nancy eagerly takes the case, and she and her grumpy best friend, a (visible) dog named Jinx, dive into the investigation.   As they follow Spot's trail, they find themselves: Every time they think Spot is right around the corner, things get more and more confusing, but Nancy knows that to a great detective, there is no such thing as a bad clue. And Nancy she's a great detective. Now she just needs to crack the case. . .