Diesel 10 was originally sent by Sir Topham Hatt to help with his work but STH didn't know that Diesel 10 was evil! He was looking for a magical steam engine, and now with his partners in crime, Splatter, Dodge and PT Boomer, he'll stop at nothing to destroy her. However in a recent turn of events, Lady, Thomas the Tank Engine and Sonic the Streamlined Tank Engine managed to crumble the viaduct and defeat him and the heavy metal diesel with his claw fell into a barge crossing a river... Again. (See my story "Missing you" for details)