Bansi O'Hara is visiting her granny in Ireland, when very strange things start to happen. First there is the swan that seems to be following them from the ferry, then the strange little man who appears in her bedroom and says he's a brownie called Pogo.
Things get even stranger when Bansi finds out that her birth fulfilled an ancient prophecy from Tir na n'Og, the land of the faeries, and that the wicked Lord of the Dark Sidhe wants to spill her blood on faery soil.
Bansi, Pogo and Tam, a handsome faery who can change into animal form, cross through the gate that separates the two worlds to try and make the prophecy come true for the good faery peoples. But the Dark Lord is waiting for them . . .