The team goes after Wo Fat and Delano for the death of an important person. Steve must resolve the issues between him and his "dead" mother, once he finds her alive and well.

The death of a polo player who literally loses his head is investigated. Meanwhile, McGarrett’s mother pays him an unexpected visit.

While the team investigates the murder of a young computer hacker, McGarrett tries to stage a long-needed reunion between his mother and his sister.

McGarrett plays cat and mouse with a smart and seductive therapist he believes murdered her patient. Meanwhile, Catherine must hunt down one of Doris's old targets who is now seeking revenge.

Five-0 investigates the murder of a traditional Hawaiian fighting master. Meanwhile, McGarrett hires a private investigator to follow his mother.

While apprehending his latest fugitive, Dog the Bounty Hunter is witness to a woman falling off a balcony to her death. Five-0's trail leads them to discover that the victim lead a double life as a roller derby player. Unable to get any useful information about the victim from her teammates, Catherine is asked to go undercover as the team's jammer. Doris comes home to find a burglar robbing her stash of sensitive information.

McGarrett must help his mother execute a covert op to retrieve an incriminating microfiche. Meanwhile, Kono’s life is in danger when she closes in on Adam’s secret.

When a plane lands on Oahu with four bodies on board and a missing terrorist detainee, the CIA tasks Five-0 with finding him before he carries out an attack on U.S. soil. Meanwhile, Kono is on the run from the police for a murder she did not commit, and McGarrett’s prison visit to Wo Fat ends with a shocking discovery.

Five-0 must free McGarrett's mother, Doris, when Catherine informs them that she was captured and is about to be executed after attempting to free Wo Fat's imprisoned father. Also, Chin loses his appeal to have Sara's adoption delayed, and she must move to Mexico.

When the CIA informs McGarrett that his mother has gone rogue on her undercover mission and may have killed her partner, Steve goes solo to Mexico to bring her home and prove her innocence.