After The Rising by Orna Ross

When Jo Devereux returns to Ireland after an absence of 20 years, the last person she expects to meet at her mother's funeral is Rory O'Donovan. The unexplained conflict between his family and hers was the one constant of Jo's childhood and caused their painful breakup. Now she's back in Mucknamore, the Irish village where they both grew up, on a historical quest, uncovering uncomfortable truths about her family's role in the conflict that became known as "The War of The Brothers", and about a killing with consequences that have ricocheted through the generations -- leading ultimately to the revolt that made her leave home.