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.
The team discovers that a dead salvage diver was looking for more than sunken treasure, Chin Ho discovers that Kono accessed his police account, and McGarrett becomes curious about what's delaying the DOD findings about his father.
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.
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.
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.
Five-0 investigates the hijacking of a delivery truck in which the driver is killed, Danny's ex-wife goes into labor, and both Steve and the Yakuza put pressure on Joe to give answers.
A woman is murdered during the governor's fund raising dinner, and Five-0 gets in trouble with the governor when the team goes too far trying to catch the killer.
While Steve's sister Mary accidentally gets caught in the middle of a plot to smuggle conflict diamonds, Five-0 and HPD get the help of an elderly ex-con recently released from prison to find the smugglers.
Just as McGarrett finally gets his hands on his arch nemesis Wo Fat in a special ops raid, he's blindsided when he finds that the Japanese Yakuza is hot on their trail and wants them both dead.
Five-0 needs the help of an imprisoned dirty cop to track down a suspect who killed Captain Fryer and set off a bomb in the HPD. Meanwhile, Joe White returns and promises to reveal Shelbourne's identity to McGarrett.