A murder happens on a ship, two days out of Panama and in the middle of the Pacific. The cruise operators decide not to turn the ship around as it goes out of helicopter range and into the Pacific Ocean, but to consult Hunter Witowski and Kieron Philips. They have just started their Miami based cruise crime investigation unit after successfully overturning a drug cartel's attempt to use a ship, at least that is how it looked in the press. Another two guests are killed and the decision is made, they have to fly out and drop into the ocean.
The Panama to Tahiti crossing is all ocean. Eleven lonely, isolated days of romance at sea that can bleed no more. Whatever is going on, has to be stopped. They board a long-range coastguard plane for a night jump into the Pacific as near to the ship as is possible. Another body is found before they change clothes, and another murder happens each night. The ship's security officer Ruby Jenkins soon develops a taste to join what she sees as a more exciting future, but it is Prisha from data wrangling in the ship's office who is seconded to help CSCI. If they can stay alive long enough to find the killer who decides to target the crew now they are in pursuit.