Upon hearing unusual noises in the mines at Lookout Mountain, Thomas and his group of friends suspect it could be a monster. So it's up to them to crack the case of the Mine Monster...and that's basically the whole thing.

While I'll admit it's better paced than Race for the Sodor Cup, the biggest problem with the story of this movie is that this is probably the only Thomas movie I've reviewed I can describe as well and truly derivative. Hear me out: Thomas tries to uncover a mystery in the mountains. Isn't that just Blue Mountain Mystery? Percy is convinced that it's a monster and there's an overall arc about being brave. Why, yes, I also saw Tale of the Brave. The engines find all sorts of hidden secrets in Sodor's underworld because yeah, I guess we also need a hint of Sodor's Legend of the Lost Treasure too. 

Granted, unlike Race for the Sodor Cup, they at least attempt to differentiate it from the originals, but the similarities keep on piling on to the point of becoming ridiculous. I will say, however, that one advantage the story has is that it can be surprisingly unpredictable. There's a lot going on in terms of twists that could potentially keep the viewer on their toes, especially with the ending twist. Another advantage is, again, the pacing. The story always moves at a brisk pace to keep the story engaging, but with a few minutes to breathe so it doesn't become too frustatingly quick. This is also helped by the tunnels' designs, which appropriately feel like a maze on top of being pretty creative. It may not be the most engaging story, and far from the most original, but I'll give the writers credit that they did the best they could with it.

This special actually does something really jarring by not introducing a single new character. Granted, they kinda treat Darcy and maybe Whiff like one, but everyone who appears in the special are just characters who were previously established in the series. So, what to do, what to do...

...how about I use this section as an excuse to talk about Bruno? I honestly think Bruno is a fantastic character. One thing I'm glad they didn't do with him that would've been way too easy for them is that they didn't make his autism his whole personality. He's also really smart and focused, but a bit of a joker who can get pretty overwhelmed at times. There's actually a scene like this in the movie where he becomes overstimulated by Percy's rambling which is honestly fantastic. It would've been so easy for Mattel to make Bruno a one-dimensional autistic stereotype like what we saw in Music or The Good Doctor, but as a neurodivergent fella myself, I'm glad they fleshed Bruno out into his own character. And knowing everything we know about Mattel's intentions with Bruno, I'm convinced that they made him a well thought out character entirely by accident.

While I'm 50/50 on All Engines Go!'s songs, I have to say that the songs in this film are pretty good. I actually like how they amped up the visuals to help them stand out, something Race for the Sodor Cup failed to do. As for the songs themselves, 'Warning: Biggest Adventure Ahead' is an alright way to kick off the journey, 'Job to Do' is a really fun finale, even if the lyrics aren't that great, and 'A Whole New Place' is really catchy, plus I do kinda like how the music sounds like the theme to The Amazing World of Gumball. I don't know why my mind went there, but when I noticed it, I couldn't unhear it.

Overall, I'd say that The Mystery of Lookout Mountain is pretty okay. The lack of any new characters is a little weird and the derivative nature holds it back a little, but the unpredictable writing and the fun songs pick up the slack. While I'd personally suggest you just go watch the other specials it rips off, like Tale of the Brave and especially Sodor's Legend of the Lost Treasure, it wouldn't hurt to check it out once just to say you at least saw it once. That's how I'm treating it, so as such, I'm gonna give it a 3/5.