A conspiracy theorist with compelling evidence that JFK's cabinet ordered his assassination is murdered. Five-0 investigates and delves into one of history's most fascinating unsolved mysteries.
Danny chaperones Grace's winter formal but terrorists seize the venue and hold everyone hostage in order to kidnap a diplomat's son. Also, Danny and Grover are shocked to learn that Will is Grace's secret boyfriend.moreless
Five-0 fights to free McGarrett's mother when Catherine informs them she was captured and is being held in a black ops site for attempting to free Wo Fat's imprisoned father. Meanwhile, Chin loses his appeal to have Sara's adoption delayed and she must move to Mexico.moreless
The murder of a medium, who was apparently scared to death by a poltergeist on Halloween, is investigated. Meanwhile, Kono and Adam are kidnapped by what appears to be a death cult.
When a cache of guns is stolen from a gun range, Five-0 discovers the culprit is intent on making a dramatic statement on gun violence.
McGarrett and Alicia are kidnapped by the serial killer who has been terrorizing the island after they discover his identity.
FBI profiler Alicia Brown is forced to join McGarrett in the hunt for the chess-piece killer when she finds a body in her bed. Meanwhile, Kono reconnects with a former surfing competitor who is now a disabled and homeless war veteran.moreless
Five-0 works with rogue MI-6 agent Harry Langford to find a terrorist planning to cause nuclear reactors across Europe to melt down. Meanwhile, McGarrett and Danny ask retired FBI profiler Alicia Brown to help them find a serial killer vigilante.moreless
Season 7 begins with the body of a serial killer being found in Five-0 headquarters with an ivory chess piece in his mouth. When a second serial killer is found dead with another chess piece, Five-0 hunts for the vigilante as fear spreads that it's not safe to travel to Hawaii. Meanwhile, McGarrett refuses to take it easy, even though he is recovering from surgery.moreless