The phrase refers to the twelfth episode of the third season of the CBS police procedural series Hawaii Five-0 , which originally aired on January 14, 2013. Episode Overview
While referred to as a "northernmost private island wildlife reserve," the plot draws inspiration from the real-life restricted island of Ni'ihau, which is often associated with the term "Kapu" (forbidden). "Hawaii Five-0" Kapu (Forbidden) (TV Episode 2013) - IMDb
The primary setting for the murder investigation.
Depending on the time zone and viewer votes, the identified killer varied: