Rachel Prince joins the Coral Queen for the holiday of a lifetime accompanied by her parents and her octogenarian friend, Lady Marjorie Snellthorpe.
Shockwaves run through the ship when a nun who is part of an exclusive religious party collapses and dies. First impressions suggest the woman died of natural causes and Rachel's best friend - cruise ship nurse - is keen to believe this is the case if it means keeping Rachel out of trouble. Rachel is not convinced and believes the death is suspicious, particularly after her father shares the nun's dying words.
The chief of security initially asks Rachel to assist as all is not what it seems within this religious order but changes his mind when the FBI come aboard.
Will Rachel listen? Marjorie is as keen as ever to do a little sleuthing of her own. Can Rachel keep Lady Marjorie safe while uncovering the mystery?
In the most dangerous challenge to date, Rachel must keep her wits about her to find out what is at stake and discover who is responsible for the nun's murder.
