Someone is stealing the chalks' lovely drawings. But he leaves some dust at the scene of the crime and only one suspect has a dusty red bottom! Sergeant Blue is quick to solve the investigation and bring the case to a happy conclusion for all!

The young chalks are busy at the chalkboard but someone keeps stealing their drawings . . .Mrs Red calls Sergeant Blue to investigate but when the culprit is caught, he absconds in a cloud of chalk dust. The chalks find another way to lure the suspect into their hands and it is only then that they discover they've misjudged the poor chalk rubber all along . . .