Evermore by Cassidy Cayman

People keep mysteriously dying at the Grancourt Castle ruins, including Jordan McCurdy’s little sister, Sophie. When an eccentric historian tries to tell Jordan that Sophie might not only still be alive, but existing in another time, he jumps at the chance to rescue her.But it does not go smoothly. Will Jordan save Sophie or doom himself? True love can’t seem to break the curse and it— or whoever is controlling it— is getting nastier all the time.

Time-travel has never been so thrilling – and dangerous – as it is in this sweeping conclusion to the Knight Everlasting series!