The Four Headed Dragon

This is a classic Hardy boys mystery. Fenton Hardy was in Alaska trying to find and stop a criminal who was planning to destroy the Alaskan pipeline. At the same time, Frank and Joe were involved in mysteries back in Bayport when their home is broken into, their father's business associate was found wandering around confused, and strange people were discovered staying in a formerly deserted mansion. As usual, they found that it was all connected and the criminal that Mr. Hardy was looking for was behind it all.