One of the passengers that boards Duncan's trains is very grumpy, and will complain about anything. Peter Sam is not so sure he has nothing to complain about, so Duncan tries his best to stop him from complaining. However, by doing this, he makes everyone else grumpy.

Percy is missing his old friend Gator and begins to mope as he thinks about the times they had together. Percy tries not to think about him, but it only makes the matter worse. Later, when he goes to Ulfstead Castle to take some trucks of sculptures to the docks, they run down the hill and crash into Stephen's mine. To find the trucks, Percy must follow Gator's advice and venture inside, all on his own.