Do Not Enter the Pass!!! is the fifteen episode of the fourth season of Thomas' Adventures Chronicles.
While visiting Our Town (Starlight Glimmer's old home), Thomas was very curious of what was inside the Pass Mountain where Starlight tried to get away with Twilight and her friends' cutie marks once. Arry and Bert shows up and told Thomas a lie that Starlight has a secret orb inside mock him saying only someone who is very brave to go in there and brings back the orb for Starlight. Thomas then shows off to the diesels and goes in the Pass, but ends up getting lost and can't find a way back out, To make matters worse the Pass Mountain is starting to crumble due to his weight. Now Starlight is the only one who knows her way round the Pass Mountain must go in there (along with Twilight, Ash, Pikachu and Percy) and saved Thomas before it collapses along with Thomas in it.