Johnny seeks Briggs's help to make a deal with Carlito, to save Lucia. Meanwhile, Mike encounters a crook with a deadly secret.
Briggs discovers that one of his housemates has evidence against him.
On day 5, Alan tries to find out what happened to Doreen after discovering her body, Julia finds a helpful friend on Level R, Sarah keeps hiding an infected patient in her room and Balleseros tries to find the mysterious Dr. Hvit.moreless
On day 4, the quarantined people on Level R force Dr. Hatake to re-etablish communication by cutting off the air supply. Meanwhile, Peter's condition worsens quickly, forcing Alan to try the untested universal treatment, Sarah has to question her rapid response test and Doreen gets closer to figuring out Balleseros.moreless
To solve a double murder, Five-0 gets some help from a conspiracy theorist.
Savino and Sheriff Lamb team up to take down Porter Gainsley. Porter put Katherine in the hospital and Ralph is convinced he killed Marilyn. Jack decides to ask Mia to marry him.
A member of a local roller derby team falls to her death in front of Dog the Bounty Hunter, as he is arresting a fugitive just a few feet away. Catherine is sent in undercover as a new member of the derby team. Steve finds out that Catherine kept a secret from him involving his mother and questions whether he can trust her.moreless
Rizzo causes difficulties for Savino when he hires Diane Desmond to sing at the Savoy. Diane just happens to be Savino's ex-mistress. Sheriff Lamb and the military police join forces when clues to a murder lead to a nearby Air Force base.moreless
Lindsay becomes injured during the attempted murder of a political candidate. The CSI team race to catch the shooter and the events in the aftermath lead to a child's death.
A video of a high school party causes the team to wonder if too much weight on a porch caused the death of a girl. Jo has to deal with her former partner bringing memories of her last F.B.I. case.moreless
When a local deep sea diver is murdered, Five-0 heads out into the ocean to find the killer.
The team investgates the kidnapping of a teenager while Kono is being investigated by Internal affairs and a profiler is assigned to the team by the new governor.
XIII escapes from a brutal rendition camp where he has been unjustly locked down for two years by NSA Director. Those who help him escape turn out to be Ex-president and a freelance killer.moreless
Five-0 must intervene when a NYPD detective goes seeking revenge against a local crime lord.