Marty cherishes the extra-special birthday present his dad gave him - a jean jacket on which he's afixed numerous buttons - because it's a tie to his father, who is sick and doesn't have much time left. So when his jacket goes missing, Marty is devastated. When his dad tells him the story of the Train of Lost Things, a magical train that flies through the air collecting objects lost by kids, Marty is sure that the train must be real, and that if he can just find the train and get his jacket back, he can make his dad better as well.

It turns out that the train is real - and it's gone out of control! Instead of just collecting things that have been accidentally lost, the train has been stealing things. Along with Dina and Star, the girls he meets aboard the train, Marty needs to figure out what's going on and help set it right. As he searches for his jacket, and for a way to fix the train, Marty begins to wonder whether he's looking for the right things after all. And he realises that sometimes you need to escape reality in order to let it sink in.

In this achingly beautiful adventure, it is the power of memories, and the love between a father and son, that ultimately save the day.