At a resort and urban complex in Oropesa del Mar, on the Levantine coast of Spain, Inspector Almanzor is ordered to investigate the death of Malory, an Irish tenant who was in a private hot tub with her husband Brendan. While not rejecting the hypothesis of suicide due to the lack of prints, the police team engages in a case in which the only clue is the presence of dry ice or carbonic snow in the water. The substance is normally harmless, but in high concentration can cause a disturbingly sweet death.
The thrilling plot leads Almanzor, a keen police officer and criminal psychologist, Roberto, the officer accompanying him, Rosa, the forensic specialist, and Isabel, the police commissioner leading the process, to focus on the couple's personal relationships, on the urban development business of Gerard, the real estate owner, as well as on the organized crime that is emerging in the area.
Using a third-person narrator who shadows different characters, the reader gains access to the personal view and memories of the victim's family and friends. Brendan conducts a parallel investigation of the crime. Adriana, a friend and colleague of Malory in a children's school, presents psychiatric problems due to the trauma generated by witnessing the scene of the possible crime. Eileen, sister of the deceased, and Sinead, her niece, and ex-girlfriend of the lifeguard Alex, reveal details of their intimate life. Anthony and Daniela, neighbors of the area, become key figures to reconstruct the life of the woman in an environment where nothing is what it seems.