Jacob Mortimer, a computer programmer from New York, feels a strange compulsion to visit Ireland. He doesn't know why but since young he had had vivid dreams about Ireland and after much internal struggle, he caves in and books a flight to Dublin with his friend, who seems strangely eager to get him there. After his arrival, strange things begin to happen and unexpected events take him to Sligo, a Northern County with loads of history. He finds himself at the top of Knocknarea, a megalithic tomb believed to be Queen Maeve's grave and, when there, all pieces come together.

His presence at that specific place throws him back in time to experience a piece of Irish history at the height of the Celtic battle the Cattle Raid of Cooley. He experiences the period in ways he never imagined, unwittingly helping Queen Maeve take the prized bull by force and gaining a night in her bed. That prize of sorts gets him killed by Queen Maeve's husband and Jacob wakes up back in Knocknarea. His whole time travel adventure had been a dream or maybe not. Back in New York he finds an item he was given in the dream in the hem of his pants. A medallion missing the center pieces. His next dream shows him the location and time in history to collect one of the missing pieces. His new destination. His next step back in time.