In Tirog, rulers of a domain are its source of magical power
Lady Trinafar, seventh child of a seventh child, should be a source and become the next ruler of Eideann after her mother Igrainid. But she is not a source. No-one knows why. When she meets Fergus in Edinburgh and he persuades her to take him to Tirog, she doesn't realise that she is triggering a series of events that will affect not only her but the future of Eideann itself.
