(In case you don't remember the story, a train with lots of dolls and toys and food for children can't get over the mountain because its engine stops working. So it keeps stopping other engines and asking for help. Eventually, a tired little engine agrees to try, and by saying "I think I can I think I can" it manages to pull the train over the mountain.)
This is Calliope's re-telling of that famous story.
Plus, can you tell that lots of adults have commented recently on how long her hair has gotten?