If Only I Knew Then is the fourth and final novel in the series that began with Nursery Rhymes, They Never Saw It Coming, and Vengeance Is Mine. Shean O Brien is on a relentless path of vengeance, driven by the tragic deaths of his younger twin brothers, who were shot while trying to run a roadblock in Northern Ireland by the British Army. Adding to his fury is the torture he endured at the hands of the police after being arrested twice. Using his cunning, O Brien has managed to escape their grasp but his thirst for retribution remains unquenched. Will O Brien succeed in his mission? And how many lives will be lost in his pursuit of justice or vengeance?