After nearly two years away from Hawaii Five-O (and a year away from television after Police Woman (1974) ended its run), Morton Stevens returned to compose the musical score for this episode and several others in the 12th season. He also orchestrated a new version of the opening theme which featured a tympani drum going down the scale in the key of C to to lead into the trumpet music. This theme (minus four seconds of drumming) is used as the closing theme for this episode only.
The credit for William Smith reads "With William Smith as James Carew," since he had not yet picked up the nickname "Kimo" (at the end of the show, McGarrett says, "Get used to it; it's Hawaiian for James"). This was the only time in the network broadcast season that the character's given name was used, but on The CBN Family Channel and in syndication in the early 2000s, this card was also used in Woe to Wo Fat (1980), the only other 12th season episode included in the syndication package.
In conversation with the Governor (who can't believe McGarrett is now taboo), McGarrett says that Captain James Cook was under a kapu when he came back to the islands a year after discovering them (without explaining why). Cook was killed while asking for supplies, presumably for violating the kapu. (This episode aired a few months after the 200th anniversary of Cook's death.)
Andy goes to a Hawaiian elder to put a kapu on McGarrett. A kapu is a curse or taboo.
This is actually a two-part episode.