When a ritualistically mutilated body washes up on the pristine river bank of Cambridge University, Detective Inspector Lewis Janeway knows his semi-retirement in the quiet college town is heating up. The story that follows is an intriguing mix of classic English detective fiction with an element of mystery that has its roots in the ancient past and Celtic ritual. When American graduate student Nick Lombard meets a mesmerizing girl in the ancient woods called Trinity Grove his life changes in mysterious ways. He begins having dreams of dark forests and armed men from Roman times. His friends worry about his obsession with the girl, Gwenillan, they have yet to meet, while Nick's life, waking and sleeping, begins to spiral into uncharted realms. The storyline provides the reader with a privileged insight into world of Cambridge student life, as Nick interacts with college porters and black-tie dinners and High Table invitations. Gradually, his carefree student life researching historical manuscripts coincides with Inspector Janeway's investigative rush to prevent the next ritual murder, since it appears that Nick may be the intended victim. As the Celtic festival of Samhain approaches, modern policing struggles to confront primeval vengeance in the shrouded recesses of Trinity Grove.