Bill and Ben are bored at the China Clay Company and are delighted to be asked to work at the harbour for the day, but they unwisely ask the trucks for advice. As a result, the yard gets in a mess, causing Gordon to be late with the Express. The next day at the company, a rockslide devastates the quarry, but Bill and Ben get all the workmen out just in time. The next day, the Fat Controller arrives on board Edward and praises the twins for saving the day. Bill and Ben think that being called "heroes" is quite a nice surprise.
