Halloween is a Thomas & Friends episode.
Thomas and Emily are sent to do an errand at the smelters on Halloween. 'Arry and Bert scare them knowing they are afraid, but when a tarpaulin falls onto Emily, Thomas, 'Arry and Bert get frightened and run away with Emily following them, thinking a ghost got her. The chase ends back at Tidmouth Sheds where the tarp flies off Emily after she steams under a signal gantry. After Sir Topham Hatt comes to see what the noise is about, Bert admits the trouble he and 'Arry caused and they are sent back to the smelters to do Thomas and Emily's work as punishment.