On 8th October 2004, Rachel Callaly was found brutally murdered in her Dublin home. Very quickly,the finger of suspicion pointed towards her husband Joe O'Reilly, who played the part of a perfect husband, fooling friends and family alike. It took three years of surprising twists and turns, bizarre encounters and ground-breaking detective work to secure a conviction.The programme has access to the key people at the forefront of this investigation including Pat Marry, one of Ireland's most straight-talking detectives, who recounts his many challenging encounters with the man he believed to be Rachel's murderer. For Pat, this case became deeply personal, a relentless mission to ensure justice was served.