Thomas is hauling a heavy special to Brendam when his siderods fall off. It happens that he broke down near an old shed. Inside, his crew discover a disused vintage lorry named Elizabeth, who they think can go to the Works to fetch new siderods.

Thomas brings the newest member of Jenny Packward's crew, Jack the front loader, to work. Jack is eager to be really useful and meets the rest of the members in his attempts to find a job. Oliver the Excavator is ordered to move a pile of rocks, but Jack foolishly tries to take them up the hill himself, leading to disaster.