Hawaii Five-0 Season 6 Ep 4 Detective Steve McGarrett (played by Alex O'Loughlin) was once a decorated Navy officer who, after retiring, became a police officer. He returned to his hometown of Oahu (the main island of the Hawaiian Islands) to investigate his father's murder. The Governor of Hawaii considered Steve a rare talent and insisted on keeping him on the island to work. She wanted Steve to assemble an elite team specifically tasked with investigating major cases – the rules were up to him, and she would provide support from behind the scenes. This team, named "Five-0" (5-0), didn't play games or go through the motions. As long as they could capture the leader of the biggest criminal gang on the island, they could do whatever it took, even if it meant shaking things up.