Mavis has an accident at Anopha Quarry and is sent to the Dieselworks. Den is sent to take her place, while Dart has to stay at the Dieselworks. However, the two always work together and they fear to be without the other.
| Creator | Britt Allcroft |
|---|---|
| Actor | John Hasler, Joseph May |
| Country | Canada, United Kingdom, United States of America |
| Production | Nitrogen Studios Canada |