On a trip to scotland with their father, meghan and william ross explore an ancient and crumbling castle-and step in to a world in the midst of a titanic battle for the future. the inhabitants of the castle are planters, using the vast power held within the fragile shells of seeds to fight against the raging power of the growing dark. their prophecy foretells the coming of the planter, a figure of immense power that will awaken the four guardians, and with their aid put down the rising evil. unknown to meghan and william, a simple act identifies one of them as the planter, and as the dark descends to destroy them, they must fight to understand their role within the prophecy, to realize their own self-worth, and to stay alive long enough that they might stand up to the dark