 Dan Williams is unable to prevent a young woman high on drugs (referred to as speed but which have the properties of LSD) from jumping off a cliff to her death. The incident puts Five-O on the trail of Professor David Stone, who was kicked out of "a Mainland university" for enticing students into using drugs. As McGarrett is building his case, the death woman s father confronts Stone and forces him to take a large dosage of the drug. Stone ends up on the same cliff and now McGarrett attempts to save his life.