When a once-brilliant, now seemingly senile inventor is murdered in his electric train workshop, the mystery is afoot. It seems no one could have come in or gone out during the period of time when the murder must have taken place, and a ticket was needed to gain admittance to the train room. This narrows the suspects down to his family and his business associates.

The Queens investigate when a wealthy industrialist and war profiteer is stabbed to death with a Chinese ceremonial dagger and then dragged out of his house and hung from a tree with a crown of thorns placed on his head.