Harold is a helicopter who is a part of the Sodor Search and Rescue Team.
Harold helped to search for Connor, Thomas, Percy, Ivo Hugh and Harvey. He was sent to spy on the Diesel Army at the LNER Sheds. He was later chased away by the latter-mentioned faction. Later, Harold had a gun mounted to him, and managed to kill Splatter and Dodge, as well as knock out D199.
Harold attended a meeting held at Knapford Station that concerned the assassin.
He also helped Officer Cody try and stop the latter mentioned criminal.
Harold then helped to transport Sir Stephen Topham Hatt, Abraham Cody, General Phoenix Brown, Kate, Stan and Justin Brown to the base of Professor's Gang. Harold was later stolen and forced to transport the Professor and his henchmen to the Sodor Steamworks, and later to an Oil Rig.
During a battle, the oil rig exploded and Harold fell into the Atlantic Ocean. It is unknown what happened to him.
Harold is a helpful rescue helicopter. Although he sometimes is known to have a rivalry with the engines, he is a good friend to them, and is always ready to help out. (Even if that means shooting down rouge diesels.)
- Harold is the only helicopter in Quest 89.