The island of Sodor, land of talking trains, has always been a realm of magic and innocence. But now Thomas the Tank Engine and his friends on the magic railroad are being threatened by diesel engines like the surly Diesel 10 and his sidekicks Splotch and Splatter. Even the magical Mr. Conductor (Alec Baldwin), who has always traveled between the train world and the human world of Shining Time Station, is losing his powers and sparkle. In the middle of this crisis, Lily (Mara Wilson), a resourceful 12 year-old, meets up with Mr. Conductor on the way to visit her lonely grandfather (Peter Fonda). With a host of whimsical, witty and wise characters, they embark on an adventure to preserve that wonderful world that exists just beyond the limits of the imagination. Brave Thomas reminds them all that "even little engines can do big things."