Code Name: Diamond Head is a 1977 Made-for-TV Movie from Quinn Martin's company. It was intended to be the pilot for a series, but the movie failed to convince the network executives it was worth a series.
The plot, such as it is, concerns Sean Donovan (Ian McShane), an evil traitor spy going by the codename "Tree," who plans to steal a biological nerve agent from the Navy and sell it for 100,000 dollars. It's up to Johnny Paul (Roy Thinnes), the eponymous agent Diamond Head (so named for the actual place in Hawaiʻi) to stop this evil spy. Rounding out the main cast are his partners in crime, Tso-Tsing (France Nuyen), a local club owner, and Zulu (played by himself), a pop singer. Tree proves more clever than they realize as he manages to kill and pose as a high-ranking Pentagon official in order to get the nerve gas. However, things quickly unravel as Tree recognizes Tso-Tsing from another operation and blows the cover of all three spies. When he makes off with the gas and Tso-Tsing, it's up to Paul to recover both and stop Tree in time.
Code Name: Diamond Head contains the following tropes:
- As You Know: A rather clumsy Back Story Info Dump by Aunt Mary on Diamond Head. It goes on for ten minutes, then Aunt Mary reinforces the Info Dump by restating what the audience was already told.
- Casting Gag: Zulu is playing the same character he did for Hawaii Five-O.
- Code Name: Some really bad ones. "Diamond Head," "Tree," "Aunt Mary"? Gee, why didn't this get picked up for a series?
- Codename Title: Protagonist Title-type Spy Fiction, named after the place in Hawaiʻi.
- Damsel in Distress: Tso-Tsing spends pretty much the entire third act in this position, though because Tree also has the nerve gas as well, she uses her predicament to lead the other two spies to their original target (and later defeats one of the henchman in the chaos of the assault on the boat).
- Dragon Lady: Tso-Tsing. Her dialog implies she intentionally plays up the image (as would the fact she has a boat named "Dragon Lady"). In reality, she's just a sweet and caring yet confident and strong woman, which fills the Chinese definition of the term.
- Failure Hero: It must be very difficult to get competent agents in Hawaii. Johnny Paul pretty much blows his own cover on his first try by attempting a scheme to lead himself to Tree that simply leads Tree to realize he's being tailed by Diamond Head himself. Later, he gets himself beat up by the same henchman several times in spite of him having a gun. Tso Tsing is incapable of retaining her own cover and blows Paul's in one go. Zulu loses the only man he intended to follow in about five minutes.
- Faking the Dead: One of the many Cliché Storm tropes in the show. Johnny does the old "they think I'm dead, it gives me an advantage" spy trope.
- Fauxlosophic Narration: Tree goes on and on about corporations knowing no national boundaries. Tso-Tsing makes retorts along the lines of selling your soul in the process.
- For Halloween, I Am Going as Myself: Tree's main disguise in the show is... exactly as himself (as Ian McShane). Master Of Disguise, indeed.
- Graceful Loser: Tree gives up rather amiably.
- Hero with Bad Publicity: Johnny's cover is of a local gambler and general ne'er-do-well.
- I Know You Know I Know: Diamond Head and Tree both know the other is aware of who and what they are.
- Ironic Echo: When Tree has the rather heavyset Zulu tied up, he mocks him with the line "Too bad we don't have an apple for his mouth." Later, when Zulu and Johnny capture Tree, Zulu repeats the same taunt to Tree.
- Master of Disguise: Tree is one of these, hence his ability to kill a high-ranking Colonel and take his place. Though he's not very good at disposing of the body without the word getting out.
- Paper-Thin Disguise: It helps when his target looks exactly like him, just with a mustache.
- Moment Killer: Johnny and Tso-Tsing are enjoying some private time in the epilogue when they're interrupted — first by Cmdr. Yarnell trying to give Johnny a new assignment, then by Zulu and Hong Kong busting in on them and bringing half of Hawaii with them for an impromptu party.
- Pilot Movie: Painfully so — a great deal of time is spent on exposition that has nothing to do with the plot and everything to do with establishing backstory for an ongoing series. Hell, the film's M even outright says "See you again, same time, same place."
- Race Against the Clock: "Aunt Mary" gives Johnny a mere thirty minutes to chase down and secure Tree and the nerve gas or the government will simply blow up his escape vessel with the gas, Tree, and the kidnapped Tso-Tsing still on board.
- Running Gag: Annoyingly done with owing the boat captain ("Hong Kong") first 50, then 100 dollars.
- Underestimating Badassery: The one thing Tree does not do. He treats Johnny and Tso-Tsing as dangerous Worthy Opponents.
- With Catlike Tread: Discussed when Johnny assigns Zulu to tail Tree's henchmen:Zulu: Like a mouse.
Johnny: [indicates Zulu's girth]
Zulu: A large mouse.