- “Help! Help!”
Thomas' Day Off is the eighteenth episode of the ninth season.
The Fat Controller announces to his engines that a new diesel engine called Dennis has arrived on Sodor and tells Thomas that he is being given a day off after his recent spell of busy work. Thomas decides to spend his day off by going to the washdown and then to Bluff's Cove. On his way there, Thomas sees the new diesel struggling to shunt some trucks of roof tiles. Dennis tells Thomas that he cannot shunt the trucks, so Thomas decides to help Dennis, even though it is his day off. Afterwards, Thomas goes off to the washdown.
But Dennis is far from happy - he does not want to take the trucks of tiles to the school because he is lazy. Thomas soon arrives back from the washdown and Dennis decides to take full advantage of Thomas' free time; he asks him to show him the way to the school. Thomas helps Dennis by telling him where to go when they reach a junction. But again, Dennis is not pleased as he watches Thomas heading towards Bluff's Cove. Then, Dennis plays another trick: he blows his horn to attract Thomas' attention. Thomas comes back and Dennis pretends that his engine had overheated. Thomas decides to help Dennis by finding another engine to help him.
Dennis is fed up that his trick had backfired on him, so he decides to run away from his work so that another engine will have to take the trucks of tiles for him. However, as he runs away, Dennis derails and ends up wheel-deep in mud (and even leaking diesel fuel). Again, Dennis calls for help, but no one is around to assist him this time.
Nearing Bluff's Cove, Thomas hears some urgent news from Percy at a signal box. The workmen are waiting for Dennis' delivery at Bluff's Cove School and do not know where he is. Thomas knows of Dennis' whereabouts and goes off to find him. When Thomas finds Dennis stuck in the mud, he is very puzzled; he thought Dennis had broken down. Dennis owns up to his actions, explaining that he is a very lazy diesel. Thomas is furious at the deception, but after seeing Dennis is in real trouble, decides to help him again. Together, they get the trucks of tiles to Bluff's Cove School. The Fat Controller is cross with his new diesel's behaviour. Dennis promises the Fat Controller and Thomas that he will be a Really Useful Engine from now on.
- Sir Topham Hatt
- Edward (cameo)
- Henry (cameo)
- Gordon (cameo)
- James (cameo)
- Emily (cameo)
- Annie and Clarabel (cameo)
- Knapford Yards
- Tidmouth Sheds
- Bluff's Cove
- Duck's Branch Line
- Sodor Shipping Company
- The Washdown
- This episode marks Dennis' first and only speaking role to date and his only appearance until the special, The Great Discovery, excluding his appearance in a tenth season learning segment. This also marks his only appearance in an episode to date.
- Going by production order, this is the twenty-second episode of the ninth season.
- This episode has similar plot elements to that of the second season episode, Percy's Predicament and the third season episode, Trust Thomas, in both of which a lazy engine tricks another into doing his work.
- The narrator says Dennis was huffing and puffing, but Dennis is a diesel.