Tim Powers (Paul Williams), known as "Stringer," is taking pictures of his girlfriend Maren Wilson (Sandra Kerns) in an out of the way location on Oahu at the same time as Duke and Sgt. Napoli (Beau van den Ecker) are tailing kumu boss Tony Alika (Ross Martin) in the same area.
While Alika's goons shoot the police car so that it goes off the road and bursts into flames, Alika gives a suitcase full of money to Howard Kramer (Robert Clarke). Stringer snaps pictures of both the money exchange and the burning wreckage. Duke is thrown free, but Napoli perishes in the fire.
At the Five-O office, McGarrett tells Danno to have the torched car's tires examined carefully. He wonders what Alika was doing in such an isolated location.
When Stringer develops the pictures, Maren recognizes Kramer as a local "political power broker" whom she has seen at parties she covers for the newspaper.
McGarrett goes to Alika's home where the mob boss says that he was "looking at property" out in the sticks. He abuses McGarrett, calling him a "big superstar cop." McGarrett says the presence of a rifle slug in one of the wrecked car's tires is very suspicious.
Kramer receives one of Stringer's pictures by courier. He phones Alika who arrives at his office to discuss the situation.
Alika berates his goons, telling them to find the photographer who took the incriminating pictures. Meanwhile, Stringer contacts Kramer and meets him in front of Kramer's office. Stringer, who is driving a pedicab, gives Kramer more pictures and demands $250,000, saying that he's "not in it alone."
Danno contacts Maren via the newspaper that purchased Stringer's photo of the burning car, saying he wants to ask some questions. She gives Danno the brush off. However, Yoshi (Michael Masegawa) overhears the conversation and tells Danno that Stringer is a pedicab driver.
Alika meets with Kramer again and views the latest photos. Alika says to set up a meeting with the photographer. Anticipating that this blackmail will never end, Alika says he will "take care of it."
Maren talks to Stringer at his place which is located in a warehouse. He shows her a two-way mirror with a special camera behind it which will take pictures if someone breaks in. She tells him she is worried that he is in big trouble. Stringer says he'll take the whole story to the cops in the morning.
Back on the street, Stringer is chased by Alika's goons and also by Danno. To escape them, he drives his pedicab into a nearby canal.
Stringer visits the Five-O office where McGarrett grills him about the car crash, saying "You're playing a dangerous game with people who make their own rules." After Stringer leaves, McGarrett orders a 24-hour tail on him. Back at his place, Stringer calls Kramer, threatening to go to McGarrett is he is tailed again by Alika's goons.
When he meets Maren, Stringer tells her that McGarrett took him into his confidence. Later, Alika's thugs attempt to follow Stringer again, but he disables their car and escapes on a bus.
Kramer is getting nervous, but Alika says he will pay up if Stringer gives both the pictures and negatives back. Alika says that if Stringer tries any more blackmail he will "blow him away."
McGarrett meets with Maren, telling her that Stringer is in a lot of trouble. After much hesitation, she gives McGarrett Stringer's warehouse address.
Kramer arrives at Stringer's, and exchanges the money for the pictures and negatives. Alika arrives with his thugs as Stringer's hidden camera records the scene. He demands that Stringer turn over everything. Saying "somebody has to pay," he orders Kramer to be thrown out of the window. Stringer quickly finds the remaining evidence. Alika gives him the money, telling Stringer to get off the islands and not come back. Alika burns the photos.
McGarrett arrives at Stringer's now empty warehouse room. He puts out an APB on Stringer and orders surveillance on Maren's apartment.
Stringer meets Maren in the garage under her apartment and shows her the money. She tells him she can't have anything to do with that, and says he should get a "real job."
Stringer returns to his place to get the film taken by the hidden camera, but McGarrett is there, having been tipped off by Maren. He tells Stringer that with the pictures of Kramer's murder and Stringer's testimony they can put Alika away. Stringer agrees.
McGarrett visits Alika and arrests him, saying "welcome to hard times, pal."