Lord of the Far Island — Victoria Holt

Lovely Ellen Kellaway knew very little about her past. Orphaned as a child and taken in by her arrogant mean-minded cousin as a 'poor relation'; she was grateful when the handsome young son of a wealthy family asked for her hand. But mysteriously, the marriage never took place.

Ellen was unexpectedly rescued from a bleak future by a summons from her newly discovered guardian, Jago Kellaway, Lord of the Far Island, off the wild coast of Cornwall.

There, on the special island of the Kellaways, Ellen was drawn deeper and deeper into the secrets of a past as alive and threatening as the present. There the enigmatic Jago Kellaway offered her the fabled island Necklace worn by the mistresses of Kellaway Castle. Was it a promise of happiness -- or a dark symbol of death?