Noelle and her friend Todd decide to investigate when her dog Rover is unjustly accused of tearing up Mrs. Ruston's tomato plants.

When her dog Rover is accused of tearing up Mrs. Ruston's tomato plants, Noelle investigates with her friend Todd and finds long yellow hairs that may point to

Todd uses clues from earwax and a pink handkerchief in order to discover which of his schoolmates has been in his treehouse.

Can the Third-Grade Detectives crack a case without Mr. Merlin?

The Third-Grade detectives try to discover why a restaurant owned by one of their friend's parents is involved in the illness of some diners.