A man from Philadelphia is given a vision that takes him halfway across the world. In the vision he meets a shaman from the time before the white men came to Haiti who tells him that the world will face huge perils in the near future. One possibility holds out hope for mankind, the other possibility leads towards a devastated world. The shaman shows the man from Philadelphia that his two young grandchildren are fated to be shamans and if the man can guide them in the right direction then the world can be saved at least for the trees if not for mankind.
This is a complex story with an environmental twist and shows us what could go wrong in our world if we stay on the path we are on.