When a man impersonating Lasalle attempts to free a young woman from jail, the team investigates both the impostor and the prisoner Pride's daughter pays him a surprise visit.
Tammy must protect a teenage girl after her father is shot in their home the rest of the team searches for a motive.
When Pride is unable to sleep due to continuing nightmares about the mysterious man in the red suit he undergoes a specialized treatment to help him figure out the man's identity an arrogant new officer joins the team.
The team investigates the murder of a JAG captain who was discovered at home by his daughter, the only heir to his large estate Sebastian is intimidated when he is put in charge of a team on his first day of training.
The team must track down a mysterious female assassin responsible for murders in Athens, Rome and London Wade's son begs her to allow him to go on a police ride-along for an article he's writing on a youth outreach program.
The team is concerned when Sebastian becomes unreachable while under cover as a new recruit.
Team Scorpion must move Happy's friend Ada, and the sterile bubble Ada lives in that protects her compromised immune system, to a secure location after a severe storm leaves the structure surrounded by dangerous debris.
Danny is shot while quarantined in the hospital unconscious, he clings to life and imagines a future for everyone.
McGarrett, Danny, Tani, and Junior are exposed to a deadly biological weapon the rest of the team has eight hours to find an antidote.
McGarrett poses as a pilot to investigate a plane crash that led to the death of a pilot in an air race.
A bank heist in progress forces Steve to make a potentially heartbreaking mistake Adam faces an empty home without Kono.
The murder of two tourists leads the team to a man who has multiple personality disorder Danny and the others hire a stress management consultant to help McGarrett.
At Halloween, the team investigates a string of murders that mirrors stories from well-known Hawaiian folklore Grover visits a man who is hours away from execution and may hold the key to a case that has plagued Grover for years.
When the HPD system is hacked and one of the Five-0's informants ends up dead, McGarrett enlists the help of hacker Aaron Wright, whom he just imprisoned.
Danny protects a coma patient who was the key witness from his last case at the Hawaiian Police Department.
McGarrett works the murder case of one of the last survivors of the USS Arizona Adam uncovers bone fragments at his new construction job.
The NCIS team tries to narrow down the motive when a Navy recruiter is murdered in a hit-and-run Lasalle worries about his brother.
A petty officer is murdered during Mardi Gras festivities Pride contemplates what to tell his daughter about his strained relationship with his father.
An agent is killed while working on a security detail for the Vice Chief of Naval Operations Brody's past is evaluated.
After learning he was poisoned with a deadly dose of radiation, a Navy lieutenant commander asks Pride and the team to solve his imminent murder.