Plot summary (original edition)

The Hardy Boys travel to Canada (somewhere near Moosonee and Moose Factory) to solve the theft of radio parts and break up an industrial spy ring.

Plot summary (revised edition)

The Hardy boys are drawn into a mystery when a group of thieves steals a collection of stuffed animals from an estate sale. Later, the Hardy boys notice a station wagon carrying stuffed animals, but when they try to give chase, the car gets away, leaving only a broken ham radio antenna behind. While they are discussing the case that their father Fenton Hardy is working on, they learn that he is after a group involved in industrial espionage and that this group uses code words very similar to what the boys have been hearing transmitted over the ham radio bands.

When the Hardy boys visit the estate to investigate the remaining stuffed animals, they are knocked unconscious and someone steals the remaining animals. They manage to get their hands on two of them and convince their friend Chet Morton, who has recently taken up taxidermy as a hobby, to open them up looking for whatever may be hidden inside. After the Lectrex plant is raided, the boys go with their father to investigate, and they notice a stuffed fox that had been on a ledge in the conference room has mysteriously disappeared.

The Hardy Boys travel to Canada (somewhere near Moosonee and Moose Factory) to solve the theft of the stuffed animals and to break up an industrial spy ring, which was the source of the leak of info coming from the Lectrex factory in their hometown of Bayport. As the boys piece together parts of this mystery, they solve the industrial spying case their father was working on, they solve the mystery of the coded transmissions on the ham radio bands, and they find out why a group was stealing the stuffed animals.

Original edition (1945)

• Ghostwriter: Leslie McFarlane
• Summary: An investigation into stolen radio parts leads the boys to northern Canada, where they locate a group of missing scientists.

Revised edition (1966)

• Revision type: Completely rewritten; some plot elements are retained, but the new story involves industrial espionage and taxidermy.
• Ghostwriter: Priscilla Baker-Carr, David Grambs