The third season of Hawaii Five-0 picks up where season two left off, with Chin Ho being forced to choose between saving his wife or his cousin.

McGarrett escorts his mother back to Hawaii and realizes she is in danger but question whether his mother may be keeping from him.

Meanwhile, the team turns to ex-con and art expert August March to help hunt down a group of thieves who rob a high-end art store in a shopping mall. The team tackles many subsequent cases including the kidnapping of a gifted computer hacker after he is released from prison and the decapitation of a polo player while atop his horse. In a special episode that jumps back and forth through time ("I Ka Wa Mamua"), the team must stop members of a terrorist cell looking to blow up multiple locations in Oahu.