The team hunts for a murderer who has been targeting serial killers, marking their corpses with an ivory chess piece.
A rogue MI-6 agent is the key to finding a terrorist who plans to cause the meltdown of nuclear reactors across Europe; McGarrett and Danny need the help of an FBI profiler to find a killer.
After finding a corpse in her bed, FBI profiler Alicia Brown joins McGarrett in a hunt for a killer; Kono reconnects with a former surfing competitor.
When the serial killer that Alicia and McGarrett have been hunting kidnaps them, it's up to Five-0 to find them before it's too late.
A cache of guns is stolen by a person looking to make a statement on gun violence; Kono and Adam are reunited.
On Halloween, the team investigates the murder of a medium who was apparently frightened to death by a poltergeist; a mysterious death cult kidnaps Kono and Adam.
Alex O'Loughlin
Steve McGarrett
Scott Caan
Danny "Danno" Williams
Chi McBride
Lou Grover
Jorge Garcia
Jerry Ortega
Meaghan Rath
Tani Rey