A man (Wydell W. Hughes) checks in for his flight at San Francisco International Airport checking two bags, one of which he is hesitant to do. Another man (Don Porter) in line keeps an eagle eye on the man as he leaves the counter. The flight is on its way to Honolulu.
Danno walks into McGarrett's office with a telex from the IRS informing of a fugitive under indictment for tax evasion: Jason T. Adams, traveling under the name of Garrison, who is carrying a large amount of cash and is on flight 842 to Honolulu. McGarrett wonders while the local IRS isn't being contacted, it's Saturday! Danno already confirmed Garrison is on board, seat 2C and notified the pilot not to alarm Garrison because they'll meet the plane.
At the airport, McGarrett, Danno and Chin meet the plane. Passengers disembark with one lady (Sally Kirkland) excitedly talking to the stewardess at the top of staircase while others wait behind her. The man from the line in San Francisco says he's in a hurry and gets her moving down the stairs. With the passengers out of the way, McGarrett and Chin board the aircraft. On board, the flight supervisor (Tim Tindall) finds a lavatory locked attempting unsuccessfully to have it unlocked from the inside. McGarrett approaches him knocking on the door himself with the same result. McGarrett wants a mechanic to remove the door but a stewardess (Jenny Sullivan) says they have a trick to unlock the door when kids get stuck. She unlocks the door to reveal a very dead Garrison! She recalls he went to the lavatory with another man following: "dark beard, glasses, seat 3B". McGarrett tells Chin to have Danno take to her to the baggage claim area to see if she can locate the mystery man. He also wants roadblocks set up around the airport in order to find the mystery man. McGarrett searches Garrison, finding his plane ticket but his baggage claim tag is missing.
In the baggage claim area, the mystery man picks up a bag and takes off for the restroom. In the restroom, mystery man discovers he's picked up the wrong bag! He asks a porter if he's seen a bag like the one he has but no luck. Meanwhile, Danno walks with the stewardess into baggage claim in order to track down the mystery man. He ducks back into the restroom removing his disguise of a beard and sunglasses. At the carousel, a couple with the excited wife grabs their bags. McGarrett joins them looking for the man too but so far no dice. When McGarrett asks various porters, the one who encountered the mystery man tells him he's in the restroom but the man is now beardless with gray hair walking right past them!
The police sketch artist (James Severson) draws up a likeness with the help of the stewardess. Danno stands by the chalkboard with a layout of the airplane showing where Garrison and his possible killer sat for 3000 miles. Chin walks in reporting the mystery man is lost because nothing was found at the airport or in the roadblocks. He also tells McGarrett there is a Jonathan Cavel to see him: IRS mainland. McGarrett agrees wanting Ben sent in as well. Cavel asks where Garrison/Adams is with McGarrett telling him he was strangled on the plane but Cavel knows this because he did it! Cavel then asks about the money but they haven't found it either as Cavel says he was carrying $600,000! This amount gets the attention of the stewardess who is still working with the sketch artist who finishes the portrait. McGarrett shows Cavel but he claims to not know him or recognize the alias "Henry Marsh". The name and address on his ticket was fake. McGarrett says Ms. Saunders, the stewardess, got a good look at him but she doesn't really recall anything else distinctive except a possible European accent. Chin and Ben walk into the office as she remembers he wiped his silverware prior to use. McGarrett tells his team to split the list of passengers to see if anyone remembers Marsh. Cavel wants a part of the list too and Danno gives him the first page before leaving.
The team spreads out tracking down passengers getting nowhere fast. People may remember him but they don't know who he is. Meantime, the couple with the excited wife settles into their hotel room. She reads from a tour book as he (Jack Dodson) takes a shower asking for his shaving kit. Betty talks all excited but goes quiet suddenly when she opens their last bag: it's full of money!
Danno and an HPD officer arrive at the couple's hotel as they debate what to do next. Betty says if they don't call the police, they're in trouble. The husband decides they're going to keep the money for "their big chance". Then there's a knock on the door. They stash the money under the bed before opening the door to Danno and the HPD officer. Danno asks if they are "Mr. and Mrs. Will Rowan" before walking in. He asks them if they've seen the mystery man, which both say no. Danno warns them not to contact him themselves because he's wanted on suspicion of murder. Betty melts down realizing the money belongs to a killer and they could be next.
Cavel goes to a room of a couple on the list breaking in. He then proceeds to tear the place apart while they're out. He becomes more ticked as he goes along not finding the money. The couple returns as Cavel is in the middle of going through the main suitcases. Cavel escapes via the balcony and into another room.
McGarrett and Ben arrive at the Hawaiian Regent to speak to Mr. and Mrs. Walter Robinson (Dick Fair, Joan Chapman) whose room was ransacked. Cavel shows up shortly after asking what's happened. McGarrett tells him to look into the room where everything was tossed. He wonders why the Robinsons were chosen out of everyone on the plane and wonders if a bag switch didn't happen. He asks Ben if Lost and Found has been checked, Ben says, "twice". McGarrett tells to check again. Just as Ben is about to leave for the airport, Cavel finds a matchbook from the International Inn. McGarrett decides he and Ben will take the International Inn and sends Cavel to Lost and Found.
Will and Betty go to Lost and Found to see if their bag is there. Betty still doesn't know what to make of the situation but Will decides to take care of things having Betty sit and be calm. He speaks to the clerk (Gary Kav) who tells them the police are looking for that bag too. He calls the stewardess lounge and finds Ms. Saunders who comes to Lost and Found taking Will and Betty out with her. She tells them a story about picking up another handbag and turning it in so long after she picked it up. She tells them about the police involvement and her understanding a federal crime is involved. She offers to take the bag from them and turn it into the police but when Will and Betty are reluctant, she threatens to make a report. They relent.
McGarrett and Ben arrive at the International Inn asking the clerk (Lydia Lei Kayahara) if the mystery man checked in. She's never seen him and she's bee on duty since 8:00 a.m. She allows McGarrett to search through the registration slips and they find Cavel's who never told them he was staying there.
At Lost and Found, Cavel identifies himself as a Federal Agent. The clerk tells him a mainland couple made an inquiry for a lost bag of the same description but Ms. Saunders took care of them. Cavel gets pushy and rude asking who Ms. Saunders is: a stewardess from flight 842. The clerk tells him he can check with Personnel on the second floor to find out Saunders' address.
Saunders arrives at her apartment with the bag as Cavel watches. Meanwhile in McGarrett's office, he tosses up the matchbook figuring out he's been had. He orders the team to "check him out". Back at Saunders' apartment, she doesn't have time to open the bag before Cavel makes his move ringing her doorbell. She hides the bag in a hamper before answering the door and allowing him entry. Cavel is not in the mood for her denials threatening to arrest her for conspiracy. When she pulls out the bag and walks back to him, he's wiping a knife and she instantly knows he's the killer mystery man! She tries talking him into going away together but he's not budging as her strangles her with his belt. He goes off about working in a government job for 32 years seeing all the criminal activity. He is going to take, regardless of the consequences. Once Saunders is dead, he opens the bag to find phone books! He rips them apart and then ransacks the apartment.
Danno and Chin walk into McGarrett's office saying Cavel is an IRS agent assigned to the Adams/Garrison case. Danno also tells him Cavel wasn't on any incoming flights that day. Chin wonders if he didn't travel under an alias, "like what? Jekyll and Hyde?" McGarrett compares Cavel's photo form San Francisco to the police sketch and determines they're the same! McGarrett is bothered why Cavel sent them to the International Inn with Danno saying it kept them busy for 15 minutes, a diversion for something Cavel was doing. McGarrett casually brings up that he's never been to the International Inn and wonders how Cavel finds it. He answers, "adequate, anonymous" and asks if he told them he was staying there. McGarrett blows it off saying it's unimportant. Cavel asks for another part of the list with McGarrett playing there's no point to it. Danno even says it's a dead end. McGarrett puts the list in his top drawer talking about Garrison's autopsy being completed. He leads Danno and Chin out of the office as Cavel says he's going to touch base with his office. As he's on the phone, Cavel pulls out the list finding the Rowans on it, noting their hotel address. What he doesn't know: McGarrett and Danno watched him from the balcony! They follow Cavel out but he soon finds them on his tail!
Cavel stops at a hotel going out the back and taking another car. The valet gives McGarrett the license number of the white station wagon: 3E-1954. McGarrett puts out an APB on the station wagon.
Will and Betty try to make a break for it but have issues getting into a cab before someone else takes it. Across the street, Cavel watches as they try to escape. He finally confronts them identifying himself as a Federal Agent and puts them under arrest.
Chin and Ben track down Cavel's other activities starting at Lost and Found where the clerk tells them Ms. Saunders the stewardess took care of it. They go to her apartment finding it trashed and her dead in the bathtub.
Cavel drives the Rowans to an out of the way place becoming philosophical as he drives. As Cavel continues driving, the HPD helicopter closes in. Cavel wants to count the money to make sure it's all still there. He finds a pullout forcing them out of the car with the luggage wanting it all opened. Will holds the bag with the money telling Cavel it's the bag he wants. At gunpoint, Will tosses it to Cavel's feet. He opens it and wants them back in the car with Betty begging for Will not to get behind the wheel. HPD units show up with sirens wailing. Behind Cavel, the helicopter hovers with McGarrett and Danno. The helicopter lands at the pullout with McGarrett ordering HPD to hold their fire. Cavel wants his freedom for the Rowans' lives and he takes off running when McGarrett tells him no deals. Will chases after him, tackling him down the mountain. Cavel keeps running jumping off the cliff to his death. McGarrett and Danno chase after him but are unable to stop him.
This plot summary Copyright Bobbi Baker ©2019. No reproduction of any kind without permission.