Bloodfever (Fever Series, Book 2)

Bloodfever is an urban fantasy novel by the American writer Karen Marie Moning, published in 2007. It is the second book of her Fever series and it continues the story of an American woman who has moved to Dublin after her sister's murder.

MacKayla Lane believed that she and her sister Alina were two ordinary young women from the American south who would marry and settle down. Then she found out that they are descended from a Celtic bloodline of sidhe-seers, people who can see the Fae, and that her own ability goes further than seeing them: she can sense the sacred Fae relics that carry the deadliest of their magic.

Her sister was found dead in a rubbish-filled alley in Dublin, and Mac has come to Ireland to find out who killed her. By the time this book opens she wants revenge more than answers, and she has learned enough about what she is to believe that she can take it. The series continues with further volumes in the same setting.