Cop and Bayonet are young moles who, instead of studying at their underground school, go traveling. On the surface of the earth, they enter the workshop to Max - a boy inventor who recycles his toys and designs unusual machines and apparatus. To test and test in the work of these inventions is a guinea pig, hedgehog, bunny, turtle and domestic rat, who work at Max testers. Cop and Bayonet are merged into a friendly team of testers and are experiencing with them the most exciting and dangerous adventures.