A 'Central Moving and Storage' truck delivers a crate near Aloha Tower. When the man (David Espinda) asks the delivery man (Robert Luck) what it is he says it's a "freezer unit". Overseeing the delivery is another man (Allen Reisner) watching from his limousine. Satisfied, he leaves the scene. Meanwhile, the crate is left in a room.
As riding down the road, the governor shows McGarrett the threat letter received. His secretary found it "tacked to the door" when she arrived for work. The package even included a sample of plutonium. Honolulu is being held for a ransom of $100 million in used bills and the governor has 36 hours to comply otherwise a nuclear device will be detonated: the letter is signed by 'Mercury'. The governor has considered the threat a hoax but after attending a governor's conference in Denver a threat in "the foreseeable future" could be made against the cities of the world. McGarrett says Honolulu is a perfect choice because Oahu is "46 by 26 miles" and impossible to evacuate in 36 hours. McGarrett asks about experts and the governor explains that's where they're going, University of Hawaii, to speak to Dr. Elias Haig (Lew Ayres) who is one of the top nuclear men in the world according to Jonathan Kaye (Bill Edwards). They arrive at the university.
Dr. Haig verifies the sample is radioactive and scanning over the plans, he says it is an accurate representation of "an effective nuclear device". He tells McGarrett and the governor the threat is real enough to take "extreme caution". He goes to say the weapon can be built and one would need a couple of "birdcages" of plutonium: the birdcages being the shipping containers. Dr. Haig tells them the material could have been hijacked off a highway on the mainland. Dr. Haig explains the damage could be ten square blocks or ten square miles there is no way to tell. McGarrett feels they're putting the cart before the horse saying it's all still a possibility but Dr. Haig questions whether they should take the risk of only considering it a possibility. McGarrett decides to cover all the bases and starts by calling Danno. The governor then plans to talk to the Federal Reserve Bank in Washington D.C. to lay his hands on $100 million. He tells McGarrett to keep him apprised before leaving. McGarrett wants Dr. Haig to give the Five-O team a crash course in how to make an a-bomb.
In Dr. Haig's laboratory, he finishes a diagram of an atomic bomb on a chalkboard. The team does their best to pay attention but Dr. Haig uses jargon they're not accustomed to. Finally, McGarrett tells him he's talking to cops. Dr. Haig tries to simplify things: the idea is for all the explosives surrounding the core to hit it all at once causing the release of neutrons. Something akin to a short-circuit, but "a billion-fold". When Danno asks about the shielding of Uranium-238, Dr. Haig explains the purpose of the shielding to allow the chain reaction to reach maximum in order to produce the largest explosion possible. Once Dr. Haig is done, McGarrett tells Chin to begin tracking down the chemicals used including orders and deliveries during the past year. He also tells Chin to grab as much manpower as he needs and if anyone balks, it's a "code-three" and refer questions to the governor's office. He then turns to Ben to check permits for high explosives and to check for any thefts of supplies. When Ben suggests checking out the regular distributors, McGarrett agrees, he wants everything checked. McGarrett asks Dr. Haig now that they know how to build one, where would one do it? A factory or warehouse? Dr. Haig says that will work. Then it's becomes a matter of how many people. Dr. Haig lists them off: draftsman/mechanical engineer, two machinists, vacuum expert, explosives expert, two chemists with one nuclear, a chemist, an electronics expert and a nuclear physicist. The timeframe would be eight months to a year. McGarrett tells Danno to start on the list with Danno starting with the physicist. Dr. Haig says they are scattered around the world so McGarrett suggests contacting A.E.C. to find out who and where they are and where they've been the last year. Before leaving, McGarrett thanks Dr. Haig for his help and asks that he stay by his phone. Dr. Haig calls the mystery man from the limousine saying, "the pigeon is in the coop. He came on wings of Mercury. Pass the word".
The crate sits in the room ticking. Meanwhile, Ben works with some HPD officers on the permits angle. Another HPD officer calls into Chin: he found the name of the company. Ben and the officers keep up their investigation from place to place finding the materials. Danno even talks to a lab technician about one of the materials: Polonium 210.
In his office, McGarrett reads an article on Anton Dolmeyer, a Swiss metallurgist, who was admitted to Queen's Hospital with severe radiation burns. It's an article Danno found but the reporter never did a follow up article and the hospital changed their story about why he died: cirrhosis, not radiation poisoning. The problem is once the mistake was found; the intern went missing and is still listed as missing by HPD! They leave for Queen's Hospital only to run into Dr. Haig outside McGarrett's office. McGarrett offers Dr. Haig to join them.
At the hospital, they speak to Dr. Beaumont (Daniel Kamekona) who is evasive with McGarrett's questions. Dr. Beaumont says they need to reference the death certificate and McGarrett asks if they keep copies on site. Dr. Beaumont goes to pull the file but that's missing too! McGarrett calls the governor for an exhumation order and they're down to 10 hours, 42 minutes.
In the morgue, Doc Bergman (Al Eben) conducts an autopsy finding no cirrhosis. Doc says he died of radiation poisoning based on epidermal burns on 2/3 of his body and massive brain-cell damage. Doc runs a Geiger counter over the body for good measure. Doc says the victim had 13 fillings, radioactive enough to "burn a hole in the top of his head".
In McGarrett's office, he goes over a posted list of names and addresses, mostly from Los Angeles. The computer was able to narrow the field of companies to a small list that ordered all the materials necessary to make the bomb. Those companies are all over the island as Chin and Ben start pinning a map. Danno walks in with immigration information on their metallurgist: he was a resident alien employed by Pacifica Refrigeration Company. Pacifica is one of the companies on the list! McGarrett calls Duke to set up a raid on the company located at 375 Nimitz Highway. They leave to help with the raid as Dr. Haig stays behind. Dr. Haig closes the door and makes a phone call from McGarrett's phone! Dr. Haig says, "the hawk has found the nest" but the mystery man is unconcerned.
Five-O shows up with HPD at the Pacifica Refrigeration Company only to find nothing except some residuals picked up by the Geiger counter! The crate continues to tick.
In the governor's office, the governor tells those gathered he and the staff have been working with Federal Reserve and the San Francisco, Seattle and Los Angeles branches to come up with the $100 million. The entire amount has been gathered, answering Jonathan's question. Jonathan tells Admiral Vance (Richard Villard) to have fighters standing by with the Admiral informing them it's still a three-hour flight "in a Phantom". McGarrett reports they still don't know who is behind the plot or the location of the bomb. Dr. Richter (Richard Angarola) proposes it's still a hoax and their actions are needless. McGarrett doesn't see it that way since the location was "sizzling with radioactivity". Dr. Richter says the residual it proof plutonium or uranium was there but not necessarily a bomb. Dr. Haig dismisses Dr. Richter's opinion because of the many lives at stake. Jonathan quells the argument with Dr. Richter wonders if the building of the bomb failed and they didn't just cut and run. The FBI representative (James Demarest) backs up the last sentiment: when things go wrong, the bad guys usually run. Another man (Lester Keiter) says paying the ransom would play right into the plotters' hands. Dr. Haig demands they stop debating and just pay up, standing up to emphasize his point. The intercom buzzes as a man with a message from Mercury is on the line. He tells the meeting the instructions for delivering the money: on unarmed man to drive an uncovered luggage trolley to their unmarked aircraft at Honolulu airport at 5:00 p.m. Once the aircraft is out of radar range, they will deactivate the bomb by remote control but the governor wants to know the location so they can dismantle the bomb. The man says instructions will be given once the plane has landed safely and the money is all accounted for. He also tells them a small demonstration that they mean business will occur at 1:00 p.m. at Kapiolani Park with a "modest radiation flash". Dr. Haig nearly melts down as both he and Dr. Richter agree this is trouble: the fire isn't the problem; the radiation to anyone within range could be lethal. McGarrett calls Danno to start the evacuation of the park and he doesn't care about the method, it just has to be done!
Danno is on board a helicopter warning people in the park to evacuate due to a bomb but it causes a panic! Meantime, McGarrett takes Dr. Haig to his house under the guise to pick up a piece of equipment. However, Dr. Haig tries to call Mercury again but the number is disconnected. Dr. Haig wants out of the entire plot but writes the symbol for Mercury on a scratch pad. McGarrett tires of waiting so runs inside to see what's keeping Dr. Haig. When he steps in, Dr. Haig pretends he has picked up a call for a wrong number. When he goes to fetch the equipment, McGarrett notices the scratch pad and pockets the top page before Dr. Haig returns to him.
Five-O, HPD and HFD respond to Kapiolani Park with the helicopter flying overhead to ensure the area is completely evacuated. Several HPD officers, McGarrett and Dr. Haig search the park as the crowds are kept back and the governor and Jonathan look on. It's found in an ice cream cart. Dr. Haig takes over as McGarrett orders all the HPD officers to "clear the area". Dr. Haig moves the cart to a restroom to mitigate the radiation exposure. The explosion happens just as Dr. Haig is cleared. Dr. Richter tells McGarrett the building needs to be sealed, as it will be weeks before it can be used again. Jonathan also orders the Phantoms to Hawaii with the ransom. The governor points to Dr. Haig and McGarrett runs to him yelling at Chin to help. McGarrett looks at the piece of paper again as Chin takes Dr. Haig to the waiting ambulance. The crate keeps ticking.
McGarrett goes to the laboratory to speak to Che Fong (Harry Endo) who tells him the symbols are for the element Mercury. McGarrett leaves the lab.
Dr. Haig leaves a tape essentially a verbal suicide note telling about the plot. McGarrett arrives at Dr. Haig's house as the tape plays. Finding the papers and bullets, but he keeps searching for Dr. Haig and finds him collapsed in another room. Dr. Haig doesn't know where the bomb is but knows it's in a wooden crate. Ben arrives, helping McGarrett move Dr. Haig off the floor and stays with him as McGarrett leaves.
The governor receives a phone call from Mercury about the $100 million. It's being loaded onto an uncovered luggage cart driven by Danno to their aircraft. Meanwhile at the Bank of Hawaii, Chin talks to a teller (Ed Fernandez) about Pacifica Refrigeration Company: their account was closed last week. Chin finds a canceled check written the day before to Central Moving and Storage and calls McGarrett. They go to Central Moving and Storage where a clerk (Wisa D'Orso) finds a freezer unit was delivered to Aloha Tower. Because that's a lot of ground, they ask who delivered the unit: Harry Luck and Joe Leoni. McGarrett calls Luck, at first getting his son but finding the answer he needs.
Five-O with Dr. Haig and HPD finds the crate opening it to reveal the bomb with the Mercury symbol prominent on its shell. Meanwhile, the unmarked airplane lands at Honolulu Airport as several HPD officers are in position to take it out. The control tower tries to make contact but no one from Mercury answers, Danno tells them "we wait".
At Aloha Tower, McGarrett introduces Lewis Chu (Earl Penaroza), HPD chief of demolitions who Dr. Haig will talk through the process of dismantling the bomb. Dr. Haig says the best thing to do is disable the remote device but McGarrett wants the whole thing disarmed. Dr. Haig tells Chu to remove the side panel. Meantime, Mercury decides to respond at the airport ordering the money to be loaded. Danno moves the tug into position. Three guys climb out of the airplane with one holding a gun directly on Danno while the money is loaded by the other two. Dr. Haig keeps walking Chu through the procedures to disarm. They reach the core, which must be removed without making contact with the sides. The money is loaded and the aircraft taxis away while Danno can only watch. However, when the core is removed, the ticking stops. McGarrett radios Danno with the go ahead to stop the airplane. Every HPD officer starts firing at it destroying the aircraft before it can take off. The airplane lies in a pile of fiery rubble on the runway. Dr. Haig is loaded into an ambulance and tells McGarrett Mercury is an evil concept, not a man or a syndicate. It'll be hard to catch too because it's quicksilver! Mcgarrett is determined to catch them anyway.
This plot summary Copyright Bobbi Baker ©2019. No reproduction of any kind without permission.