O'ahu goes on lockdown as the team looks for a terrorist who is using weaponized drones on civilians; McGarrett and Danno attend a review with a psychologist.
While a Navy Seal is on a secret mission, his young daughter is kidnapped; Danny must find $18.5 million in order to save his brother.
Three female thieves unwittingly make themselves serious targets when they take something during a tour bus robbery; Danny searches for his brother's money.
When a man from Detroit is killed on the streets of Oahu, the team is shocked to discover the killer's motives; Chin risks everything to help Danny.
McGarrett meets a woman who helps him reopen the last cold case his father investigated before dying.
On Halloween, the team hunts a serial killer who mimics murders from a cult slasher film; Jerry is abducted by counterfeiters.
McGarrett experiences what would have happened to the team had they taken a different path when he is kidnapped by Wo Fat.
Sons become the prime suspects in the murder of their parents; Aunt Deb shocks McGarrett when she returns to the island with her new fiance.
When a cowboy is poisoned, Max must work with a rival medical examiner; McGarrett wants Danny to steal a Christmas tree.
An old-school private detective helps the Five-0 solve the murder of a young woman who secretly worked as an escort.
When a tourist unknowingly transporting a stolen Van Gogh is murdered, Kono and Chin go under cover into the world of black market art; McGarrett asks chef Masaharu Morimoto to train Kamekona for a shrimp cook-off.
When a neurosurgeon is murdered right before a procedure, the stunning truth about a decades-old disappearance of four school boys is revealed; McGarrett's car is stolen.
A patient with a contagious and deadly strain of bird flu is kidnapped -- and the people responsible plan to weaponize the virus.
Kono must fight for her life after discovering a notorious criminal's identity; Adam's ties to his formerly corrupt family business leaves Kono feeling concerned.
The members of the Five-0 investigate a journalist's past after he is killed; as Valentine's Day draws near, a text mix-up causes Danny to overreact.
Five-0 and an ATF agent (Melina Kanakaredes) from California team up when a serial arsonist targets couples in Oahu; Amber's abusive ex tracks her down while she is on a romantic getaway with Danny.
Danny and McGarrett work on their relationship as they pursue a woman who escaped after a diamond robbery.
When Chin and Danny are taken into custody over past deadly transgressions, McGarrett turns to Joe for help.
McGarrett and Odell come under assault at the barbershop while trying to protect a young man being hunted by a gang; Jerry is accused of a series of home invasions.
The wife of one of Grover's closest friends falls to her death; Dr. Shaw and Danny are stuck in an elevator with a body that needs processing.
After a murder takes place at a convention of Elvis impersonators, the victim's body is stolen; Gabriel asks Chin for help.
When a dead woman is found in a hotel suite belonging to three married, hungover men, the team must help them retrace their steps as they try to remember what happened -- and find the killer.
During a solo outrigger trip, Kono encounters bad weather and must fight for her life; the Five-0 investigates a man in trouble for cooking meth.
After apprehending a fugitive, a bounty hunter is murdered; Rachel reveals a secret to Danny that has ramifications; Chin talks to McGarrett about his concerns regarding Adam.