Many people who know the story of the 1916 Rising have heard the harrowing account of the wedding of Grace Gifford and Joseph Plunkett in Kilmainham Gaol, on the dat before his execution for his part in leading the Rising. However, what is not so well known is that Grace had five sisters, all of whom were involved in the Irish nationalist movement, including Murial who was married to Thomas MacDonagh, and Nellie and Kate who were both imprisoned for their Republican activities.

Unlikely Rebels tells the story of the sisters, who were, by virtue of their forebears and training, most Unlikely Irish Rebels. The daughters of staunchly unionist parents and raised in the Protestant faith, all of them embraced the Republican movement wholeheartedly. When the opportunity arose for them to play their part in the struggle for Ireland's freedom, they seized it, despite the hardship and in some cases tragedy that it brought them.