Mei-Ling Wan (Lorna Ho), a young woman with a 10-month-old baby, buys a fish at the Oahu Market for $3. When she gets home, she starts to cut it open, but finds a gold bar inside. She is annoyed, saying "Fresh from the docks!" An Asian guy sneaks in through her back door. He has a switchblade, which he flicks open. She screams. Her baby is crying. The guy takes the gold bar, presumably after he kills her (there is no blood all over the place like we get with the "new" Five-Zero).
HPD and Five-O including Steve McGarrett are at the murder scene. U.S. Treasury agent Philip Grey (Richard Denning!) arrives, wondering if traces of gold HPD has found on the woman's kitchen knife are connected to "a big size chunk" of a shipment of millions of dollars worth of illegal gold heading to Hawaii from Japan. Grey says, "We'll just have to continue the 24-hour alert on anything and everything moving in or out of the island."
At a meeting later in the Five-O office, McGarrett orders his men to find out who killed Mei-Ling. HPD's Howard Kealoha (Doug Mossman) says they lifted a print from the front door frame belonging to "Kim-Tung Chang, male, Chinese, 31. Weight, 210. Height, 6-foot-1. Four arrests, no conviction. All for gambling."
Johnny Fargo (Kaz Garas) is seen taking part in a back room crap game. He kisses some blonde dame with him for luck. When the cops and Five-O raid the place a few minutes after this while looking for Chang, he is not there, and neither is Fargo.
Chang's body is subsequently fished out of the harbor. McGarrett talks to Al (Mark LeBuse), owner of a cocktail bar on the docks. Al says that Chang, "a born loser" who worked the aku boats came into his place a lot, usually broke. Al has a cheque that he recently cashed for Chang still in the register, which shows that Chang worked for Fargo.
McGarrett and Kealoha go to see the medical examiner who says he found flecks of gold under Chang's fingernails during his autopsy.
McGarrett pays a visit to Fargo, who is unloading fish from his boat on the docks. Fargo says that Chang, a "beach bum," worked for him "a couple of days ago" as well as occasionally in the past.
After McGarrett leaves, lawyer Paul Dennison (Paul Richards), shows up at the dock and also talks to Fargo, who he tells "My people are worried about you." Fargo says that Dennison should thank him for the way he took care of Chang. Dennison warns Johnny: "That temper of yours. That could get you into trouble."
Chin Ho, who is doing surveillance at the docks, follows Dennison.
Fargo is seen on his boat out in the ocean with his men stuffing gold bars into fish which are tagged by clipping one of their tail fins. Later, at a fish processing factory, the bars are removed and tallied up by Fargo.
McGarrett gets a call that Chin Ho is in the hospital with a fractured skull. Chin says that he followed Dennison, who met with Wong Tou, local gambling syndicate boss. While Chin was watching them, he was punched out and later dumped in an alley.
McGarrett goes to Dennison's office, where the lawyer plays dumb. McGarrett writes Chin's name on Dennison's desk blotter and tells him "If he doesn't come out of this a whole man, nothing will save you." When Dennison says, "Why would one of your men be following me?" McGarrett replies, "When I get the answer, don't be surprised if you're in jail for the rest of your life."
At the Five-O office, Kono fills McGarrett in on Dennison: "Sharp operator. Walks a tight line, leaning on the shady side. Defends pushers, prostitutes, bagman for the number boys. Principal client, gambling syndicate." Including Wong Tou.
Danno has the dope on Fargo: "Ex-GI, dishonorable discharge, crooked gambling. Spent three years in Tokyo, black-market operations. Big man with the ladies. Came here one year ago. Started tuna fishing two months later."
McGarrett recaps: "Gambling syndicate's got big money to invest. Best buy in today's market is gold. Treasury tells us there's a big shipment of yellow stuff headed this way from Japan. Okay. Who's got contacts in Japan? Who's got the facilities for smuggling it in? Who could act as a middleman between Dennison and Wong Tou? And who did Kim-Tung Chang, the flecks of gold under his nail, who did he work for?" Danno replies, "Johnny Fargo. The word from the dock says that Johnny's been bragging he's gonna have his first million before he's 30."
McGarrett and Grey decide to trap Fargo, offering him a million dollars for his gold, by using an undercover agent named Andrea Clair Dupré (Marj Dusay) who is "made-to-order for a lover boy like Fargo." Johnny shows up at her hotel room, saying "I was playing five card stud. Somebody slipped me a sixth card," meaning her business card. She offers to buy his gold, but only after beating him down in price from $45 an ounce to $37.25, which is just above the going rate of $35.
After Fargo leaves, McGarrett, who has been in adjoining rooms with Grey and two other agents, tells Grey that he wants to get more than just Fargo who is "small fry." He will get word to Dennison via the grape vine that Fargo is trying to cross him and Wong Tou. Word gets through to Dennison quickly. He tells Wong Tou (Richard Loo) that Fargo is "gonna steal the gold and sell it to someone else." Wong Tou replies, "Then I see no advantage in letting him live."
Fargo is seen piloting his boat to a buoy where a sack containing the next shipment of gold bars is tied to the bottom.
At the hospital, Chin Ho undergoes surgery and the operation is successful.
Fargo calls Dupré, who meets him at a pre-arranged location near the Ulu Mau Village. Her case containing the money has a tracking device in it. Dennison and Wong Tou are following the two of them. McGarrett, Danno and Kono are also following, along with several cops in cars. Fargo drives into a parking garage and he switches with Dupré to another car parked in the street below. Dennison and Wong Tou follow them; they are busted by Five-O as they try to leave. Danno tells Dennison that in the cannery that he and Wong Tou own, the cops found a "room full of gold." This raid was thanks to a search warranty from the Attorney General. Danno says, "If I were you, Mr. Dennison, I'd find myself a real good lawyer."
Fargo drives with Dupré to a dock where his boat is anchored. There Fargo shows her the gold, but he pulls out a gun. Dupré shows him the money, and he orders into the ship's hold. Fargo leaves the ship just as McGarrett drives up nearby. After trying unsucessfully to escape, Fargo makes a run for his boat, but is shot by McGarrett and falls into the harbor.
After Dupré gets out of the hold, McGarrett says "I wonder how far he would have gotten with a million dollars worth of phony money" as the wind blows the bills into the harbor.