Antagonistic members of an American/Irish blended family seek pathways to reconciliation following tragedy. After the tragic death of favorite son Michael O'Connell, his young widow Kiri dedicates her life to fulfilling the pledges she made to him as he lay dying in the Syrian desert--to nurture their neighborhood in Dublin; to provide safety, love and joy for his nieces and nephews; to fold friends into their family; and to bear and raise his children as the two of them dreamed they would do together. Irish Catholic patriarch Thomas opposes his daughter-in-law's controversial actions until he realizes that any boy child she may produce will be his only grandson to carry on the O'Connell family name. The births of cerebral MT and firecracker Katie fill his life with new joy but not enough time left to revel in it. Desperate to assure his legacy but faced with his mortality, Thomas surprises the O'Connell family with his plans for their futures. Kiri struggles against the yoke that Thomas places on her and clings to the fairy whispers and Blackbird feathers that she believes Michael sends her way. Her mother Paula, best friend Henry Callaghan, shirttail cousin Bitsy the harpist, Clayton Moriarty's granny and New Zealand sheep baron Jack MacKenzie unveil pieces of the puzzle that lead Kiri to discover the secrets held within the Celtic Circle and the answer to the question that haunts her for six decades--Does one's vow of unconditional commitment last forever?