 McGarrett receives a cryptic letter and a photo of a woman with an "x" drawn through it. The woman was stabbed repeatedly. Later, another is killed the same way and Five-O gets another letter. The victims both worked at the same company, Hawaiian Amalgamated Industries. The company is headed by the headstrong Martha, who employs two nephews, Arnold and Charlie. The killings are a ruse, intended to create the impression of a psychopath killer on the loose. In reality, the killer is Charlie and he kills Martha so he can inherit his share of her estate. He also stabs himself to make it appear he was a target of an attack. But Martha s will has Arnold take over running the company and a relatively modest trust for Charlie. The development spurs Charlie to try to kill Arnold and frame him for the killings.