At his mentor's request, McGarrett persuades Max to redo the autopsy on a SEAL, thought to have committed suicide, in order to investigate his murder. Meanwhile, Chin Ho worries about Kono hanging out with a group of dirty ex-cops, including Frank Delano.

The Five-0 take to the beautiful waters off Hawaii to investigate the murder of a deep sea diver known for his valuable shipwreck finds.

The FIVE-0’s investigation into the murder of the state’s women’s volleyball coach leads them to find out more bad news about Kono, and Chin Ho reconnects with his former fiancée, Malia.

Five-0 is in hot pursuit of a shooter who guns down one of their own, while another team member is forced to choose which of their kidnapped loved ones will live.

The team goes after Wo Fat and Delano for the death of an important person. Steve must resolve the issues between him and his "dead" mother, once he finds her alive and well.