Terry and his friends work hard building a new highway. They get tired, but they are proud of their work.

A salesman comes with some “super powerful fuel.” He claims this new fuel will help them do more work and get less tired. He tells the machines they will have more fun if they use it.

Three machines decide to try the new fuel. They soon begin to cause problems on the job. They also become very cranky when others ask them about their problems.

Terry and his friend, Suzy Scraper, realize their friends are in trouble. They help the boss and police catch the salesman. Then, the machines welcome their friends back to the job site.

They all decide to say “Yes” to doing good work and “No” to using super powerful fuel.