1863, in the midst of a convoy heading West on its way to a better life, Martha Jane’s father gets hurt. It is she therefore who must drive the family wagon and look after her siblings. Martha Jane has never felt so free. And since it’s more practical, she doesn’t hesitate to slip into trousers. But this is too bold for the leader of the convoy. Accused of theft, Martha has to run away. Dressed as a boy, searching for the evidence of her innocence, she discovers a world change where her original personality will assert itself. An adventure full of dangerously encounters, which will reveal the mythical Calamity Jane.