The episode opens with McGarrett boarding ship for a two-week deployment as a reserve Navy commander. But after only a short time, he's assigned back to Oahu for a joint civilian-Naval investigation of a mysterious bombing that's killed one intelligence officer and wounded another. Following the trail has McGarrett visiting both San Diego and Costa Mesa, California, as well as considering four possible suspects both in and out of the Navy back in Hawaii -- until the trail begins to point to the involvement of his old nemesis, Wo Fat.
—aldanoli