Steve McGarrett torna a casa a Oahu per trovare l'assassino di suo padre. Il Governatore gli offre la possibilità di gestire la propria unità operativa chiamata "Five-0".
The island's leading tsunami expert is kidnapped on the same day that ocean reports indicate that a huge tsunami is headed to Hawaii. However, Five-0 soon suspects that the report is a hoax and is related to the kidnapping.
Five-0 turns up the heat on a crime boss after the safe house of an undercover police officer who infiltrated his organization is compromised and his wife is killed.
McGarrett and Chin Ho try to rescue and protect a federal witness on the run from assassins, while Danny tries to get to the bottom of his daughter and ex-wife's carjacking.
The team investigates the death of a commercial fisherman whose body was found in an unexpected place, while the imminent death of Chin Ho's aunt could reveal surprising new details about the stolen drug money.
While investigating the murder of a professional photographer, Five-0 discovers a connection to a local bookie. Meanwhile, Chin Ho covers for his uncle and claims that he has the stolen police money.
After one of Governor Jameson's assistants is killed, McGarrett discovers that the governor may have been working with Wo Fat and may have been the target of his father's investigation.
McGarrett escapes from prison and sets out for revenge on Wo Fat, with the help of his now-disbanded Five-0 team and the man who trained him in the Navy.
The governor appoints a new member to the Five-0 team, who is trying to find a kidnapped 15-year-old girl. Meanwhile, Kono comes under investigation by Internal Affairs.
With the help of Joe White, McGarrett tries to find a killer targeting members a of a Navy SEAL team, while Kono contemplates a job offer from the underworld.
While Five-0 tries to figure out who killed a well-known Honolulu businessman, Joe gets an unwelcome visitor while trying to search for answers about the video.
Two ghost-hunting filmmakers are killed at a historic traditional burial site, and when the team discovers more dead bodies at the site, they suspect that they could be after a serial killer.
The team tries to uncover the identity of a man who recently had plastic surgery but was found dead in the trunk of a stolen muscle car--which will hopefully lead them to his killer.
While Five-0 investigates the death of a muckraking reporter, Jenna returns to ask McGarrett for help finding her fiancé in North Korea--which is actually part of Wo Fat's revenge plot--and Joe White leads the mission to bring them home.
As the gang gets ready for Chin Ho's wedding, Five-0 discovers that a man shot in a military bunker was in Hawaii to search for his missing son, and Steve begins to suspect that Joe is hiding secrets about the investigation from him.
A team of drug dealers kidnaps a busload of school children in order to get Five-0 to return the drugs they confiscated, while Joe White goes on a personal mission to uncover the identity of "Shelbourne" before Wo Fat does.
