Frank and Joe saw a man enter. He carried a tool kit and a cutting torch. Taking a drill from the toolbox, he searched for a spot on the wall and began to drill. As Frank and Joe jumped from their hiding place, the man put a match to the cutting torch and a blue flame shot out with a deadly hiss. "Stand where you are," the intruder snarled, "or I'll cut you in two!" The Hardy Boys investigate a series of mysterious warehouse robberies, carried out by a highly organized and deadly ring of thieves.