A 1903 coin is being worked on as a police escort detail arrives at the Ilikai Hotel as the Pacific Coin Convention is taking place there. Danno and Chin escort a highly valuable briefcase into the hotel as the other coin continues to be worked with its date being changed to 1913. The briefcase is opened in an office under heavy police guard with the manager (Jimmy Borges) opening the vault. Mr. Haviland (Robert Costa) has a 1913 Liberty coin of which there are only five in existence and he tells the manager it's insured for $100,000.
At an ocean lookout, an older man (Jack Morris) holds up the coin he worked on and says it will stand up under high magnification. He claims it's well worth $1000 but the man he's meeting with shoots him dead with .38 silenced gun! The man (James Grahlmann) gets into his car leaving the area.
Later McGarrett arrives on scene as Danno briefs him: Henry Andecker and his car, dead maybe an hour. Che Fong (Harry Endo) believes it's a professional job because the bullets exploded on impact and they probably had Mercury cores. McGarrett wants the book on Andecker as he climbs in his car to leave.
A con (Eugene Troobnick) pulls a sleight of hand trick with a deck of cards for the HPD guard before being released. The guy who killed Andecker posted his bail! He then takes the con to a beach where Arnie is reunited with Millie (Hildy Brooks) before another man (Victor Buono) interrupts. The three eat lunch on the beach as the man explains he arraigned for Arnie's release. They get down to business: the man wants Arnie to steal a 1913 Liberty Head nickel and exchange it for the fake he just gave Arnie. The man offers Arnie $10,000 to pull the job abut Millie has reservations about the whole thing especially when the man gives Arnie an envelope with his hotel reservations and his credentials as a rare coin collector. The man cautions them if they get greedy, it could be costly.
Millie walks ahead of Arnie at the hotel still not liking the whole deal. Millie wants an end to their criminal life but Arnie sees it as an easy $10,000 to make. Millie points out the man knows everything about them but they don't know anything about him. Millie is worried Arnie will get caught and if he does, it's major trouble but nothing will happen to the man who hired them. Arnie tries to reassure her it's going to work "like a Swiss watch" but Millie isn't convinced.
At the Ilikai Hotel, the coin convention commences with several rare coins being highlighted. Danno and Chin along with several HPD officers, keep up the security net as Arnie enters the floor as "Wilson Davis". He goes to Haviland asking to examine the 1913 nickel as he wants to make a bid on it. Arnie holds the nickel under a magnifying glass and when Haviland's eyes wander for a second, the switch is made and Chin is standing right there! Arnie walks out but when he's in the hallway, the alarm sounds and HPD closes all exits to the hotel including the front doors where Arnie wanted to walk out of. Arnie puts the nickel into the newspaper machine.
Haviland is beside himself as McGarrett and Five-O investigate what happened including speaking to "Mr. Davis". McGarrett returns to where the coin was swiped and wants everyone on the bidder list checked again as well as though who have been searched. Haviland explains the coin started out as a 1903 nickel and someone changed the 0 to a 1, possibly a jeweler or a metal engraver. Haviland is worried the coin won't be recovered but McGarrett tells him they'll do what they can.
Arnie keeps a watchful eye on the newspaper machine where he dropped the nickel in to hide it. After hours of waiting, they hit pay dirt: the newspaper guy who collects the coins has and they follow him on his rounds.
In McGarrett's office, so far no word from Haviland's insurance company for the coin. Ben walks in on information about Andecker: he was convicted in Europe of forgery with stock certificates. Chin says that makes him an engraver and he was killed the day before the real coin was stolen. McGarrett tells Jenny to contact Hans Vogler (Johann Strasser) of Interpol. Meanwhile, McGarrett shares the autopsy results: the bullets were definitely Mercury core and a bit of shell showed the bullet was probably Belgium or West German in origin. Chin is perplexed asking, "Andecker got hit by a European cat?" McGarrett is pretty sure that's the case.
Arnie keeps following the newspaper guy who continues to empty newspaper machines of their coins. As the newspaper guy reaches the car, Arnie jumps out grabbing the coin bag and they wrestle around causing coins to flay everywhere. The newspaper guy goes to the front of the car and gets his gun firing as Millie runs over to help Arnie. The men wrestle for the gun but the newspaper guy winds up shot and in the back of his station wagon. Arnie grabs as many coins as he can as a lady who heard the shot calls the police. Arnie sees the guy is breathing and eventually runs for his own car taking off.
In McGarrett's office, the call from Vogler comes through. McGarrett asks for information on Eric Damien, perhaps a past associate of Andecker's, including photo and current whereabouts. Vogler tells McGarrett to be wary of Paul Anthony who is a skilled assassin. McGarrett asks for his information too. Once he off the phone, he tells Chin and Ben Damien has one rule: those who cooperate with the law wind up missing or dead. Danno walks in with a break: Wilson Davis' credentials didn't check out all the way. Danno already has a sketch artist working with Haviland on a portrait and once it's complete, McGarrett wants an APB out on "Davis".
The man behind the scheme to steal the coin tries to contact Arnie but he doesn't answer the phone. He double-checks with the hotel clerk and verifies Arnie is in his room. He calls Paul so they can go look for their hired thief.
Arnie desperately searches for the nickel but it's not among the coins they have. He determines he's got to go back to the alley to find it. Millie is not enthused at all about the turn of events thinking the newspaper guy is dead.
In McGarrett's office, Danno has a report of a mugging happening five hours after and less than a mile away from the theft. Jennings, the newspaper guy, is currently in a coma and the Ilikai is on his route. Duke (Herman Wedemeyer) walks in with Damien's photo and other information including Paul's description. They are traveling together as they were in Tokyo two weeks ago. Damien is the man behind the scheme.
Damien and Paul arrive at Arnie's hotel looking for him and the coin. Arnie and Millie are about to leave when Arnie sees Paul in the hallway. They elude him and Paul returns empty-handed. He drops Damien off at the house where they're staying with Damien telling him to stay at the hotel and once the couple returns bring them to the house. Damien enters the house only to be greeted by McGarrett! They dance around each other for several minutes as Damien claims to not know anything about the nickel or Andecker. Damien says he's in Hawaii for a holiday and nothing more. McGarrett warns him he may "find the running room a little short" and the mongoose always wins against the cobra.
Arnie and Millie search the alley again but Millie returns to the car watching a grandfather (C.K. Huang) and his grandson pick up a coin dated 1913, the same year the grandfather was born, "that is good luck". They continue walking down the street as Millie calls out to Arnie and they follow them.
Duke arrives at Iolani Palace as McGarrett and Chin discuss the coin swap with Danno listening in. Duke runs into the office with information on Davis: real name is Arnie Price and HPD had him in custody two days ago on a bunco charge. Somebody made bail and it's being followed up. McGarrett wants Arnie picked up because if Damien had the coin he would have been long gone by now.
The grandfather and grandson keep walking with Arnie and Millie right behind them. The grandson finds something to buy in a Chinese shop and pays for part of it with the found nickel. The merchant gives the nickel as change to a pair of lady customers who are in the shop. The ladies walk out and now Arnie and Millie follow them. The ladies stop at a vending machine where Millie feeds it coins hoping for it to spit out the right change. Arnie follows the ladies to a restaurant with Millie catching up not finding it in the machine. They watch the ladies pay for some food as another guy walks in snatching her purse. Arnie and Millie chase after the guy hoping the nickel is in the purse. A locked chain link gate corners the guy and he tosses the purse to Arnie who searches for the nickel but doesn't find it. Arnie loses it going to the guy yelling and shaking him. Millie is able to pull him off and they run back to the restaurant only to find it closed. They decide to go to a bar after their exhaustive search and order a pair of drinks. Arnie pays for them with cash as they cost $1.30. The bartender returns with the change and among the coins: the nickel! They are ecstatic and happily leave the bar with the nickel. It's short lived though as a pair of HPD officers pick him up on new charges: grand theft and assault to commit murder!
Arnie is brought to McGarrett's office where McGarrett lays it out for him: he's in big trouble because of his involvement with Damien. McGarrett is only interested in nailing Damien and is not that interested in Arnie and Millie. Jennings will pull through but Arnie is "facing a complicity rap for murder". McGarrett convinces him to testify and Arnie hands over the nickel as well. The phone rings, Chin calls in reporting Damien and another man just left the hotel with a woman. McGarrett figures they now have Millie and asks if there was a way to contact Damien. Arnie gives him the phone number Damien gave him: a mobile number. McGarrett dials it putting Arnie on to meet somewhere and putting the call on speaker. Damien tells him to walk in front of a cement factory "at the corner of Pahanui Mahanua" and he'll be picked up. The car will be easily recognized since Millie is in the front seat. After the call, Damien sets a timer for ten minutes.
Arnie paces in front of the cement factory where the car shows up a short time later. Damien demands the nickel, which Arnie hands over and tells Paul to drive to the hotel. Damien realizes they're being followed and is let out at the next intersection leaving the "radio phone" in the car telling Paul he'll contact him as soon as he's able. Chin radios Damien has been dropped off with McGarrett responding as he and Danno close in. Meanwhile, Damien grabs a cab as Paul plays rough with Chin taking a shot at him as they drive down the road. Arnie then starts choking Paul and the car loses control driving onto a boat ramp into the water. McGarrett and Danno catch up seeing what happened. They run into the water with Chin to rescue everyone in the limousine: Danno takes Paul, Chin helps Arnie and McGarrett carries Millie to safety just before the car explodes!
Damien makes a run for it only to be stopped by the Park Lane and Danno's demand of "out". Damien gives up the nickel that McGarrett tosses in the air to be caught by Danno. McGarrett informs Damien it's the fake, he produces the real one from behind Damien's ear ordering, "book him".
This plot summary Copyright Bobbi Baker ©2019. No reproduction of any kind without permission.