Freelance reporter Darcy Farthing boards a luxury cruise ship for a trip to beautiful Australian seaports with family and friends, where a baffling murder mystery challenges her investigative skills. The crimes begin when a small town Kansas woman traveling with a class reunion tour group is plagued by an attack of yellow crazy ants-a dangerous invasive species-as well as an illness caused by mysterious food-borne bacteria, and the odd cancellation of an onshore tour. The bizarre but relatively minor incidents escalate when the ants injure more passengers and crew members. Soon, a peculiar death on the streets of Adelaide, and attempted murders on board the ship threaten to cause panic. It is obvious that a crew member or passenger is targeting individuals, but who is it, and why? Meanwhile, Darcy is distracted by daughter Rachael's uncharacteristic behavior and intense friendship with a charismatic passenger. Reluctant to make waves, Darcy tries to suppress her concerns. She turns her full attention to the crimes when evidence is found in her friend Brooks' stateroom and the security chief names him as the sole suspect. Brooks is clearly innocent, but the chief is inexplicably reluctant to conduct a more thorough investigation to clear him. Then Darcy's best friend, Sid, who is also Brooks' fiancé, becomes the latest victim. Clue by clue, with husband Mick's help Darcy uses her skills to reveal a homicidal master of disguise and world class computer hacker intent on exacting revenge related to a twenty-year-old crime.