When you stand up for what's right, you'd better be ready for the fight of your life!

In an effort to protect the environment, the students of Bayport High have organized a massive recycling campaign -- Project Planet Earth. Even the industrial giant United Plastics has expressed support for the idea. But someone has developed a more sinister plan -- a campaign of sabotage designed to poison the entire project.

Frank and Joe's investigation turns urgent when the dirty tricks turn deadly. A United Plastics security guard is crushed in a factory machine, and the Hardys have evidence of blackmail and murder. But they won't be able to prove a thing until they put their own lives at risk...penetrating the company's defenses and uncovering the darkest, dirtiest secret of all!