Murder on Board by Trevor Johnston

Rose Merrin is dying. Together with her husband Gabriel and their best friends Billy and Muriel they travel from Rosslare in Ireland to Roscoff in France on the overnight ferry known as 'The Booze Cruise'. It is to be their last holiday together. On the journey a murder takes place. Gabriel and Billy who are police officers take control of the investigation. They uncover a web of murder, fraud and sex crimes, in what is a harrowing investigation.