Restless after having no new cases for months and with their partners away on a safari, when a call comes through about a seemingly straightforward case in the Florida Keys, the girls accept the job no questions asked in hope of some excitement.

Arriving at their destination they discover the case revolves around a man who's been killed - speared through the stomach by a marlin as he was taking a selfie. All involved are adamant it was simply a bizarre fishing accident, except for the Wassingers, a dithering couple at risk of losing their family home due to the death. It turns out the reason the Wassingers are convinced of foul play is because they have a witness. Unfortunately for Gladdy and the team, the witness is other-worldly . . .