A failed Quinn Martin pilot for a series starring a Hawaii-based government counter intelligence agency run by the indomitable Aunt Mary. In this, his only adventure, Diamond Head has to prevent the evil Tree from stealing a deadly nerve toxin gas and selling it to foreign powers. To help Diamond Head is the Dragon Lady and Zulu.
| Actor | Role |
|---|---|
 Roy ThinnesJohnny Paul | Johnny Paul |
 France NuyenTso-Tsing | Tso-Tsing |
 ZuluZulu | Zulu |
 Ward CostelloCaptain Macintosh | Captain Macintosh |
 Don KnightH.K. Muldoon | H.K. Muldoon |
 Ian McShaneSean Donovan / Father Horton / Colonel Millard Butler | Sean Donovan / Father Horton / Colonel Millard Butler |
 Eric BraedenErnest Graeber | Ernest Graeber |
 Dennis PatrickCommander Yarnell | Commander Yarnell |
| AAlex HenteloffDr. Edward Sherman | Dr. Edward Sherman |
 Frank Michael LiuHikaru Sakai | Hikaru Sakai |
 Eric ChristmasFather Murphy | Father Murphy |
 Ernest HaradaHero Yamamoto | Hero Yamamoto |
 Harry EndoDr. En-Ping | Dr. En-Ping |
 Lee StetsonTanner | Tanner |