On the fourth anniversary of his father's death, McGarrett meets a woman who helps him reopen the last unsolved case his father worked on before his death.
It's Halloween and Five-0 must track down a serial killer who is copying murders depicted in a cult slasher film. Meanwhile, McGarrett must help Jerry after he is kidnapped by the counterfeiters he has been tracking.
Five-0 enlists the help of an old-school private detective to solve the murder of a young woman who was secretly working as an escort. William Forsythe guest stars as the old-school private detective. Doug Savant and Eric Roberts also guest star.
McGarrett enlists Joe's help after Danny and Chin are arrested for deadly past transgressions. Terry O'Quinn and Jimmy Buffett return.