DI Humphrey Goodman and the team are left stumped when millionaire environmentalist and scientist Dan Hagen is shot on his boat while out at sea. The evidence seems to point to a robbery gone wrong, but with no other boats reported in the surrounding area, DI Goodman suspects foul play by one of Dan’s crew. With the other four members of the group diving on the coral reef and in plain sight of one another at the time of the murder.