Mason Watts, a park ranger and professional big wave surfer, dies while surfing a big swell near his post on the Channel Islands. His father and close Eppes' family friend, Keith, suspects foul play and urges Don to investigate. Don looks over the case file with Colby, and they discover that Mason's death was staged to look like an accident. Looking for a motive, the FBI focuses on urchin divers that had had lost their license after a run in with Mason, but that quickly turns in to a dead end. However, they soon discover that the islands were being used to grow marijuana. They continue to investigate this angle, and go on to learn that Mason had stumbled on his ex-girlfriend and a surf rival running the farming operation and had tried to arrest them. However, his ex-girlfriend got the drop on him hit him in the head with a kayak oar, killing him, and then she and her partner staged the surfing accident to cover their tracks.
