When Irish beauty, SIBELLA COTTLE sets her sights on the rakish HARRY LYNCH-BLOSSE, she is determined to steal his heart and make him hers; but Harry is not free to love her. He is still married to Emily Mahon, a staunch Catholic who refuses to have their marriage annulled. Even if she were to release him, his ambitions would be better served by marrying Lady HARRIETT BROWNE, a cousin of Lord Altamont. Despite himself, Harry falls for Sibella and following a night of passion she becomes pregnant. Her plight is desperate. They elope to his mother's home in Suffolk in 1774 where Harry persuades a solicitor to confirm his freedom to marry. Sibella's hopes are dashed at the altar when a letter from Ireland denies Harry's right to marry. Harry promises to marry her once his annulment comes through. Although distraught, Sibella recovers to focus on her pregnancy. Her mood lifts when she gives birth to a healthy boy, MICHAEL.

Having returned to Balla, County Mayo, Harry becomes the 7th Baronet after his father dies. Good fortune follows when Sir Harry is elected to the Irish Parliament and Sibella delivers twin girls, CECILIA and Mary Anne. In the following years, Sibella gives birth to her second son, John, and after a further pregnancy, to her third daughter, Bridget. During this time, Harry establishes the Balla Volunteers to protect Ireland from invasion. Lady Harriett assists him in this task much to the chagrin of Sibella. Worse is to follow when Sibella intercepts a letter from JAMES CUFFE MP, a trustee to Harry's estate. In the letter, Cuffe urges Harry to abandon "that woman" and marry Lady Harriett now that he is free to do so.

Sibella is terrified and seeks the advice of the witch, JUDY HOLIAN, who recommends the spancel, a love charm guaranteed to spellbind Harry for life. Aided by Judy, Sibella makes a spancel from a strip of skin cut from a corpse initially unaware that the body is that of Harry's illegitimate daughter, Ellen Colgan. Sibella must ensure that Harry never finds out the source of the spancel or he would surely abandon her. Haunted by the spectre of witchcraft, Sibella's position is precarious. Her epic struggle for survival is interwoven against a background of intrigue, rebellion and romance. This extraordinary story is based on real events in 18th century Ireland.