In this feature length special, Thomas leaves Sodor in disgrace after being blamed for an accident and the engines of Sodor are forced to defend their home against an invasion of enemies lead by Theodore Osborn and Diesel 10.
Bertie and Bulgy agree that the bus with the fewer passengers will be the one who is rerouted. Bulgy cheats, but Bertie comes out on top with some help from his railway friends.
There's a mystery on the Island of Sodor as Henry, Gordon and James' tenders disappear overnight. Could it be the work of aliens or is there a simpler explanation?
Henry is disappointed to be given goods work on the day of a special Easter Egg Hunt at the Town Hall and tries to do both jobs. In doing so, he almost ruins the entire event for everyone.
Philip and a team of explorers go on the hunt of Sodor's Lost Emerald, but they end up finding something of much more significance to the North Western Railway.
In this Christmas Special, Mighty Mac finally get their wish and become two separate engines. But it's not long before they realise just how much they need each other.